Exhibit 99.1

NEWS RELEASE

FOR IMMEDIATE RELEASE

CENTURY BANCORP, INC. ANNOUNCES RECORD EARNINGS FOR Q3, UP 24%; ASSET

GROWTH TO $3.0 BB; REGULAR DIVIDEND DECLARED

Medford, MA, October 9, 2012—Century Bancorp, Inc. (NASDAQ:CNBKA) (www.centurybank.com) (“the Company”) today announced net income of $14,261,000 for the nine months ended September 30, 2012, or $2.57 per Class A share diluted, an increase of 14.1% compared to net income of $12,504,000, or $2.26 per Class A share diluted, for the same period a year ago. Total assets increased 8.1% from $2.7 billion at December 31, 2011 to $3.0 billion at September 30, 2012. For the quarter ended September 30, 2012, net income totaled $5,682,000, or $1.02 per Class A share diluted, an increase of 24.0% compared to net income of $4,582,000, or $0.83 per Class A share diluted, for the same period a year ago.

Net interest income totaled $47.0 million for the first nine months of 2012 compared to $41.3 million for the same period in 2011. The 13.9% increase in net interest income for the period is due to a 10.5% increase in the average balances of earning assets, combined with a similar increase in average deposits. The net interest margin increased from 2.49% on a fully taxable equivalent basis in 2011 to 2.58% on the same basis for 2012. This was primarily the result of prepayment penalties that were collected during the third quarter. Also, interest expense decreased primarily as a result of the continued decline in market rates.

The provision for loan losses decreased by $350,000 from $3.6 million for the nine months ended September 30, 2011 to $3.3 million, for the nine months ended September 30, 2012, primarily as a result of changes in the composition of the loan portfolio. The Company capitalized on favorable market conditions for the first nine months ended September 30, 2012 and realized net gains on sales of investments of $1.1 million, compared to $1.2 million, for the same period in 2011. FDIC assessments decreased for the first nine months of 2012, primarily as a result of a decrease in the assessment rate, offset somewhat by an increase in the assessment base. The Company’s effective tax rate increased slightly from 7.5% in 2011 to 8.1% in 2012. The Company’s income tax rate has remained low primarily as a result of tax-exempt income.

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At September 30, 2012, total equity was $178.1 million compared to $160.6 million at December 31, 2011. The Company’s equity increased primarily as a result of earnings and other comprehensive income, net of taxes, offset somewhat by dividends paid. The Company’s leverage ratio stood at 6.95% at September 30, 2012, compared to 7.02% at September 30, 2011. This decline in the leverage ratio is due to an increase in assets, offset by an increase in stockholders’ equity. Book value as of September 30, 2012 was $32.10 per share compared to $29.43 at September 30, 2011.

The Company’s allowance for loan losses was $18.7 million or 1.75% of loans outstanding at September 30, 2012, compared to $16.6 million or 1.68% of loans outstanding at December 31, 2011 and $16.0 million, or 1.68% of loans outstanding at September 30, 2011. Non-performing assets totaled $5.9 million at September 30, 2012, compared to $7.0 million at December 31, 2011 and $7.4 million at September 30, 2011.

The Company’s Board of Directors voted a regular quarterly dividend of 12.00 cents ($0.12) per share on the Company’s Class A common stock, and 6.00 cents ($0.06) per share on the Company’s Class B common stock. The dividends were declared payable November 15, 2012 to stockholders of record on November 1, 2012.

The Company, through its subsidiary bank, Century Bank and Trust Company, a state chartered full service commercial bank, operating twenty-four full-service branches in the Greater Boston area, offers a full range of Business, Personal and Institutional Services.

Century Bank and Trust Company is a member of the FDIC and is an Equal Housing Lender.

This press release contains certain “forward-looking statements” with respect to the financial condition, results of operations and business of the Company. Actual results may differ from those contemplated by these statements. The Company wishes to caution readers not to place undue reliance on any forward-looking statements. The Company disclaims any intent or obligation to update publicly any such forward-looking statements, whether in response to new information, future events or otherwise.

Century Bancorp, Inc. and Subsidiaries

Consolidated Comparative Statements of Condition (unaudited)

(in thousands)

Century Bancorp, Inc. and Subsidiaries

Consolidated Comparative Statements of Income (unaudited)

For the Quarter and Nine months ended September 30, 2012 and 2011

(in thousands)

Century Bancorp, Inc. and Subsidiaries

Consolidated Year-to-Date Average Comparative Statements of Condition (unaudited)

(in thousands)

Century Bancorp, Inc. and Subsidiaries

Consolidated Selected Key Financial Information (unaudited)

(in thousands, except share data)