Exhibit 99.1

FOR IMMEDIATE RELEASE:

Guaranty Bancorp Announces 2012 First Quarter Financial Results

·                  Net income improved for the fifth consecutive quarter

·                  Net loan growth of $11.8 million, or 1.1% during the quarter

·                  Core deposit growth of $39.7 million, or 3.6% during the quarter

·                  Adversely classified assets decline for seventh consecutive quarter

·                  Net interest margin expansion of 7 basis points on a linked quarter basis to 3.93%

DENVER, April 19, 2012 — Guaranty Bancorp (Nasdaq: GBNK), a Colorado-based, community bank holding company, today reported first quarter 2012 net income of $2.9 million, or $0.03 earnings per basic and diluted common share, compared to a net income of $0.5 million for the quarter ended March 31, 2011. Earnings per basic and diluted common shares were $0.03 for the first quarter 2012 as compared to a loss per basic and diluted common share of $0.02 for the first quarter 2011. The earnings per common share calculation for the first quarter 2011 included a non-cash adjustment of approximately $1.5 million related to the regular quarterly paid-in-kind dividends on the Company’s Series A Convertible Preferred Stock.

Paul W. Taylor, Guaranty Bancorp’s President and Chief Executive Officer, stated, “We have continued our positive trend into 2012 with respect to the key operating metrics of our Company. We continued to grow income, expand margin, improve efficiency, increase loans and core deposits, improve asset quality and maintain strong capital and liquidity.”

Mr. Taylor continued, “Our commitment to the communities we serve is evidenced by $11.8 million in net loan growth. After loan pay-offs and maturities, this represents $116.6 million in new loans and additional credit on existing lines during the first quarter 2012. We are very pleased with our strong level of core deposits, which grew by 3.6%, or $39.7 million, in the first quarter with noninterest-bearing deposits representing 35% of total deposits at March 31, 2012. While our primary focus was on growth during the quarter, we also continued to reduce our level of classified assets. At March 31, 2012, our level of classified assets to capital and allowance for loan losses was 35.6%.”

1

The improvement in net income in the first quarter 2012 compared to the same quarter in 2011 is due to a $1.0 million reduction in provision for loan losses, due to improved asset quality, a $1.0 million reduction in noninterest expense, mostly due to lower expenses related to other real estate owned and lower FDIC assessments, and a $0.6 million increase in net interest income. These improvements were partially offset by a $0.2 million decrease in noninterest income due primarily to a decrease in net gains on sales of securities.

Key Financial Measures

Income Statement

Balance Sheet

Net Interest Income and Margin

Net interest income for the first quarter 2012 remained consistent with fourth quarter 2011 at $15.3 million and increased slightly as compared to first quarter 2011 of $14.7 million. The Company’s net interest margin of 3.93% for the first quarter 2012 reflected an increase of seven basis points over the fourth quarter 2011 and an increase of 51 basis points from the first quarter 2011.

2

In the first quarter 2012, both interest income and interest expense declined by $0.1 million on a linked quarter basis, resulting in a relatively consistent level of net interest income. The decline in interest income was due to a slight decline in loan fee income, while the decrease in interest expense was primarily due to a $17.2 million decline in average time deposits, mostly higher-cost, brokered time deposits. At March 31, 2012, our brokered deposit balances were $0.1 million.

Net interest income increased $0.6 million in first quarter 2012, as compared to the same quarter in 2011, due to declines in interest income and interest expense of $1.6 million and $2.2 million, respectively. The decline in interest income was primarily due to an unfavorable volume variance of $1.4 million and an unfavorable rate variance of $0.2 million. The unfavorable volume variance is due to a decrease in average earning assets of $177.4 million. This decline was primarily due to a $92.9 million decrease in securities and overnight funds and an $84.5 million decrease in average loans. The decline in interest expense was due to favorable volume and rate variances of $1.2 million and $1.0 million, respectively. The favorable volume variance was primarily related to a decline in average time deposits of $250.3 million and a decline in average Federal Home Loan Bank (“FHLB”) borrowings of $53.0 million.

Noninterest Income

The following table presents noninterest income as of the dates indicated:

Noninterest income of $3.1 million in the first quarter 2012 reflects an increase of $0.3 million as compared to the fourth quarter 2011 due mostly to the increase in net gains on sales of securities recognized in the first quarter 2012.

As compared to the first quarter 2011, noninterest income declined $0.2 million in the first quarter 2012 primarily due to a net decrease in the gain on sales of securities. The gain on sale of securities in the first quarter 2011 was due to the sale of certain securities to reduce duration within the investment portfolio.

3

Noninterest Expense

The following table presents noninterest expense as of the dates indicated:

Noninterest expense decreased $0.4 million in the first quarter 2012 to $14.5 million on a linked quarter basis. The decline is primarily due to decreases in intangible amortization expense and loan-related legal expenses of $0.3 million and $0.2 million, respectively. These decreases are partially offset by increases in salaries and benefits and net other real estate owned expense of $0.1 million each. The decrease in intangible amortization expense is due to the accelerated method of amortization adopted by the Company at the time of the related acquisitions. Loan-related legal expenses declined due to reduced levels of loans in the workout phase. Salary and benefit expense increased due to annual payroll tax cycle increases and net other real estate owned expense increased due to adjustments to annual property tax accruals.

Noninterest expense decreased $1.0 million in the first quarter 2012 as compared to the first quarter 2011. Reductions in noninterest expense include: net other real estate owned expense of $0.4 million primarily due to lower levels of net write-downs, FDIC assessments of $0.3 million due to changes in the assessment rules effective April 1, 2011, intangible amortization of $0.3 million due to the accelerated amortization method discussed above, and professional fees of $0.3 million due to expenses associated with an executive management search in 2011. These reductions in expenses were partially offset by an increase in salary and benefit expense of $0.2 million due to an increase in bonus and incentive accruals.

Balance Sheet

At March 31, 2012, the Company had total assets of $1.7 billion, which represented a $26.8 million increase as compared to December 31, 2011 and a $118.0 million decline as compared to March 31,

4

2011. The increase in assets from December 31, 2011 consists primarily of an $11.8 million increase in loans, net of unearned discount, and a $15.2 million increase in securities. As compared to March 31, 2011, the decline in total assets is primarily due to declines in cash and due from banks of $79.5 million, primarily overnight funding, a decline in loans, net of unearned discount, of $16.2 million, a decline in loans held for sale of $14.2 million and a decline in securities of $7.8 million.

The $11.8 million growth in total loans, net of unearned discount in the first quarter 2012 as compared to December 31, 2011 was primarily related to increases in residential and commercial real estate loans of $25.3 million, partially offset by a decline in commercial loans of $14.5 million. At March 31, 2012, our residential and commercial real estate portfolio included 32.0% owner occupied properties and 6.3% multi-family properties. We have capacity to extend additional credit on residential and commercial real estate loans as evidenced by our regulatory concentration ratios discussed below.

Since March 31, 2011, the ratio of construction, land and land development loans to capital fell by 24 percentage points to 53% at March 31, 2012. During the same period, the ratio of commercial real estate loans to capital rose slightly by four percentage points to 265%. These concentration ratios remain below the regulatory commercial real estate concentration guidelines of 100% for land and construction loans and 300% for all investor real estate loans.

The following table sets forth the amounts of our loans outstanding (excluding loans held for sale) at the dates indicated:

The following table sets forth the amounts of our deposits outstanding at the dates indicated:

5

At March 31, 2012, noninterest-bearing deposits as a percentage of total deposits increased to 35.0% as compared to 34.3% at December 31, 2011 and 29.2% at March 31, 2011.

Non-maturing deposits increased $39.7 million in the first quarter 2012 as compared to the fourth quarter 2011 and $103.4 million as compared to first quarter 2011. Time deposits decreased $14.6 million in the first quarter 2012 as compared to fourth quarter 2011 and $202.7 million as compared to the first quarter 2011. Time deposits continue to decrease primarily as a result of management’s efforts to reduce the overall level of higher cost time deposits, particularly brokered and internet deposits. Total brokered deposits at March 31, 2012 were $0.1 million as compared to $10.2 million at December 31, 2011 and $133.3 million at March 31, 2011. Brokered deposits represented 0.1% of total time deposits at March 31, 2012 as compared to 5.0% at December 31, 2011 and 37.1% at March 31, 2011. In addition, internet deposits at March 31, 2012 were $0.2 million as compared to $0.3 million at December 31, 2011 and $19.7 million at March 31, 2011.

Borrowings were $110.2 million at March 31, 2012 and December 31, 2011 as compared to $163.2 million at March 31, 2011. The Company elected to payoff $51.0 million of FHLB term notes in September 2011. The weighted average rate of these advances was 3.5% with maturity dates that ranged from November 2011 to February 2014. The entire balance of borrowings at each balance sheet date consists of term notes with the FHLB.

Regulatory Capital Ratios

All of the Company’s and its subsidiary bank’s regulatory capital ratios are above the highest regulatory capital threshold of “well-capitalized” at March 31, 2012. The Company’s and its subsidiary bank’s actual capital ratios for March 31, 2012 and December 31, 2011 are presented in the table below:

Generally, the allowance for loan losses is included in total capital for regulatory purposes; however, it is limited to 1.25% of total risk-weighted assets. At March 31, 2012, approximately $12.8 million of the subsidiary bank’s allowance for loan losses was disallowed from being included in total risk-based capital under the regulatory capital rules, or approximately 0.92% of our consolidated risk-weighted assets. No deferred tax assets were disallowed for purposes of computing consolidated Tier 1 capital other than the deferred tax valuation allowance in our financial statements.

6

Asset Quality

The following table presents select asset quality data (including loans held for sale) as of the dates indicated:

(1)Past due loans include both loans that are past due with respect to payments and loans that are past due because the loan has matured, and are in the process of renewal, but continue to be current with respect to payments.

(2) Excludes loans held for sale.

The following table summarizes our past due loans by class (including loans held for sale) as of the dates indicated:

7

During the first quarter 2012, nonaccrual loans increased $2.8 million primarily due to the addition of a single natural gas energy loan of $8.7 million, prior to partial charge-off. Management expects this loan to be mostly paid off by the end of second quarter 2012. At March 31, 2012, total classified loans, excluding non-accrual loans, declined $3.6 million and loans classified as special mention and watch declined $2.8 million on a linked quarter basis. Other real estate owned decreased by $1.0 million during the first quarter 2012 as compared to the fourth quarter 2011.

As of the date of this release, the $1.3 million in loans 90 days or more past due at March 31, 2012 have been renewed.

Net charge-offs in the first quarter 2012 were $5.6 million as compared to $2.2 million in the fourth quarter 2011 and $2.2 million in the first quarter 2011. The increase in net charge-offs is primarily the result of a single charge-off of $3.9 million related to the natural gas energy loan previously discussed.

The general component of the allowance for loan losses decreased from $31.2 million at December 31, 2011 to $27.5 million at March 31, 2012. The general component represented 2.5% of loans, net of unearned discount, at March 31, 2012 as compared to 2.8% of loans, net of unearned discount, at the end of the previous quarter. The coverage ratio, defined as allowance for loan losses divided by nonperforming loans, decreased from 129.3% at year end 2011, to 97.1% at March 31, 2012.

The Company recorded a provision for loan losses in the first quarter 2012 of $1.0 million, as compared to $1.0 million in the fourth quarter 2011 and $2.0 million in the first quarter 2011. The lower level of provision for loan loss over last year reflects the overall improvement in asset quality.

Shares Outstanding

As of March 31, 2012, the Company had 106,138,255 shares of common stock outstanding, consisting of 101,043,255 shares of voting common stock and 5,095,000 shares of non-voting common stock. At March 31, 2012, total common shares outstanding include 2,240,353 shares of unvested stock awards.

8

Non-GAAP Financial Measures

This press release includes non-GAAP financial measures related to tangible assets, including tangible book value and tangible equity ratio, all of which exclude intangible assets.

The Company discloses these non-GAAP financial measures to provide meaningful supplemental information regarding the Company’s operational performance and to enhance investors’ overall understanding of the Company’s core financial performance. Management believes that these non-GAAP financial measures allow for additional transparency and are used by some investors, analysts and other users of the Company’s financial information as performance measures. These non-GAAP financial measures are presented for supplemental informational purposes only and should not be considered a substitute for financial information presented in accordance with GAAP. These non-GAAP financial measures presented by the Company may be different from non-GAAP financial measures used by other companies.

The following non-GAAP schedules reconcile the book value per share to the tangible book value per share and the GAAP equity ratio to the tangible equity ratio as of the dates indicated:

9

About Guaranty Bancorp

Guaranty Bancorp is a bank holding company that operates 34 branches in Colorado through a single bank, Guaranty Bank and Trust Company. The Bank provides banking and other financial services including commercial and industrial, real estate, construction, energy, consumer and agricultural loans throughout its targeted Colorado markets to consumers and small to medium-sized businesses, including the owners and employees of those businesses. The Bank also provides private banking and trust services, including personal trust administration, estate settlement, investment management accounts and self-directed IRAs. More information about Guaranty Bancorp can be found at www.gbnk.com.

Forward-Looking Statements

This press release contains forward-looking statements, which are included in accordance with the “safe harbor” provisions of the Private Securities Litigation Reform Act of 1995. In some cases, you can identify forward-looking statements by terminology such as “may,” “will,” “should,” “could,” “expects,” “plans,” “intends,” “anticipates,” “believes,” “estimates,” “predicts,” “potential,” or “continue,” or the negative of such terms and other comparable terminology. These forward-looking statements involve known and unknown risks, uncertainties and other factors that may cause the Company’s actual results, performance or achievements to be materially different from any future results, performance or achievements expressed or implied by such forward-looking statements. Such factors include, among others, the following: failure to maintain adequate levels of capital and liquidity to support Company’s operations; the effect of the regulatory written agreement the Company and its bank subsidiary have entered into and potential future supervisory action against the Company or its bank subsidiary; general economic and business conditions in those areas in which the Company operates; demographic changes; competition; fluctuations in interest rates; continued ability to attract and employ qualified personnel; ability to receive regulatory approval for our bank subsidiary to declare dividends to the Company; adequacy of our allowance for loan losses, changes in credit quality and the effect of credit quality on our provision for credit losses and allowance for loan losses; changes in governmental legislation or regulation, including, but not limited to, any increase in FDIC insurance premiums; changes in accounting policies and practices; changes in the deferred tax asset valuation allowance; changes in business strategy or development plans; changes in the securities markets; changes in consumer spending, borrowing and savings habits; the availability of capital from private or government sources; competition for loans and deposits and failure to attract or retain loans and deposits; changes in the financial performance and/or condition of our borrowers and the ability of our borrowers to perform under the terms of their loans and other terms of credit agreements; political instability, acts of war or terrorism and natural disasters; and additional “Risk Factors” referenced in the Company’s most recent Annual Report on Form 10-K filed with the Securities and Exchange Commission, as supplemented from time to time. When relying on forward-looking statements to make decisions with respect to the Company, investors and others are cautioned to consider these and other risks and uncertainties. The Company can give no assurance that any goal or plan or expectation set forth in forward-looking statements can be achieved and readers are cautioned not to place undue reliance on such statements, which speak only as of the date made. The forward-looking statements are made as of the date of this press release, and the Company does not intend, and assumes no obligation, to update the forward-looking statements or to update the reasons why actual results could differ from those projected in the forward-looking statements.

10

GUARANTY BANCORP AND SUBSIDIARIES

Unaudited Consolidated Balance Sheets

11

GUARANTY BANCORP AND SUBSIDIARIES

Unaudited Consolidated Statements of Operations