Exhibit 99.1

Altra Reports Second-Quarter 2013 Results

First Half 2013 Cash Flows from Operating Activities up 36% to $33 Million

Gross Profit Improves 20bps to 30.0% Despite Lower Sales

BRAINTREE, Mass., July 25, 2013 — Altra Holdings, Inc. (Nasdaq: AIMC), a global manufacturer and marketer of electromechanical power transmission and motion control products, today announced unaudited financial results for the second quarter ended June 29, 2013.

Financial Highlights

Management Comments

“Despite lower sales we are pleased with the results,” said Carl Christenson, Altra President and CEO “In light of the weakness in certain of our end markets we took actions where appropriate to reduce costs, including tight spending controls, shortened work weeks and selective headcount reductions. Several of our capital intensive end markets, including metals, mining and energy, were particularly weak during the quarter, resulting in lower-than-expected second-quarter revenues and net income. The weakness in these markets was offset by significant improvements in the underperforming businesses on which our team has been focused. Gross margin was up 20 basis points year over year to 30% and Non-GAAP net income kept pace with the second quarter of last year.”

Business Outlook

“We continue to make progress with our strategic growth and profitability initiatives, such as the acceleration of Lean, the implementation of our new strategic pricing program, the expansion of our presence in emerging geographies and the development of innovative new products. In addition, our strong balance sheet puts us in a solid position to continue pursuing our acquisition strategy,” said Christenson. “Although we do not expect the second half improvement that was anticipated by many of our customers to materialize it does appear that May marked the nadir for incoming orders. Orders improved in June and this positive trend has continued into the third quarter. In addition, it appears that customers are currently satisfied with the inventory reductions they have achieved and a very modest improvement in economic conditions is anticipated. Consequently, we expect that the second half of the year will be in line with the comparable period a year ago. Given the lower-than-expected results in the first half of the year and the lack of any apparent catalyst for significant economic growth in the second half, we are revising our guidance for the full year.”

The Company is now forecasting sales in the range of $715 to $730 million and non-GAAP diluted EPS of $1.52 to $1.64 for 2013. Altra expects its tax rate for the full year to be approximately 31% to 33% before discrete items. The Company expects capital expenditures in the range of $20 to $23 million, and continues to expect depreciation and amortization in the range of $28 to $30 million.*

The Company will host an investor conference call to discuss its unaudited second-quarter financial results today, July 25, 2013, at 5:00 PM ET. The public is invited to listen to the conference call by dialing (877) 407-8293 domestically or (201) 689-8349 for international access and asking to participate in the ALTRA conference call. A live webcast of the call will be available in the “Investor Relations” section of www.altramotion.com. Individuals may download charts that will be used during the call at www.altramotion.com under “Events & Presentations” in the “Investor Relations” section. The charts will be available after earnings are released. A replay of the recorded conference call will be available at the conclusion of the call on July 25, through midnight on August 8, 2013. To listen to the replay, dial (877) 660-6853 domestically or (201) 612-7415 for international access (replay ID # 417875). A webcast replay also will be available at www.altramotion.com.

Altra Holdinhs, Inc.

(1) - tax impact is calculated by multiplying the estimated effective tax rate for the period of 31.3% by the above items

(2) - tax impact is calculated by multiplying the estimated effective tax rate for the period of 32.0% by the above items

(3) - tax impact is calculated by multiplying the estimated effective tax rate for the period of 30.1% by the above items

(4) - tax impact is calculated by multiplying the estimated effective tax rate for the period of 31.9% by the above items

About Altra Holdings

Altra Holdings, Inc., through its wholly-owned subsidiary Altra Industrial Motion, Inc., is a leading global designer, producer and marketer of a wide range of electromechanical power transmission and motion control products. The company brings together strong brands covering over 40 product lines with production facilities in nine countries. Our leading brands include Boston Gear, Warner Electric, TB Wood’s, Formsprag Clutch, Wichita Clutch, Ameridrives Couplings, Kilian Manufacturing, Marland Clutch, Nuttall Gear, Stieber Clutch, Twiflex Limited, Bibby Transmissions, Matrix International, Inertia Dynamics, Huco-Dynatork, Warner Linear, Bauer Gear Motor and Powerflex.

* Discussion of Non-GAAP Financial Measures

As used in this release and the accompanying slides posted on the Company’s website, non-GAAP diluted earnings per share, non-GAAP income from operations and non-GAAP net income are each calculated using either net income or income from operations that excludes acquisition related costs, restructuring costs, and other income or charges that management does not consider to be directly related to the Company’s core operating performance. Non-GAAP diluted earnings per share is calculated by dividing non-GAAP net income by GAAP weighted average shares outstanding (diluted). Non-GAAP free cash flow is calculated by deducting purchases of property, plant and equipment from net cash provided by operating activities.

Altra believes that the presentation of non-GAAP net income, non-GAAP income from operations, non-GAAP diluted earnings per share and non-GAAP free cash flow provides important supplemental information to management and investors regarding financial and business trends relating to the Company’s financial condition and results of operations.

Forward-Looking Statements

All statements, other than statements of historical fact included in this release are forward-looking statements, as that term is defined in the Private Securities Litigation Reform Act of 1995. These statements include, but are not limited to, any statement that may predict, forecast, indicate or imply future results, performance, achievements or events. Forward-looking statements can generally be identified by phrases such as “believes,” “expects,” “potential,” “continues,” “may,” “should,” “seeks,” “predicts,” “anticipates,” “intends,” “projects,” “estimates,” “plans,” “could,” “designed”, “should be,” and other similar expressions that denote expectations of future or conditional events rather than statements of fact. Forward-looking statements also may relate to strategies, plans and objectives for, and potential results of, future operations, financial results, financial condition, business prospects, growth strategy and liquidity, and are based upon financial data, market assumptions and management’s current business plans and beliefs or current estimates of future results or trends available only as of the time the statements are made, which may become out of date or incomplete. Forward-looking statements are inherently uncertain, and investors must recognize that events could differ significantly from our expectations. These statements include, but may not be limited to, those relating to the Company’s strategic growth and profitability initiatives, end market expectations, plans to enhance bottom line performance, plans to gain market share, improvement in orders, the Company’s acquisition strategy and its guidance for full year 2013.

In addition to the risks and uncertainties noted in this release, there are certain factors that could cause actual results to differ materially from those anticipated by some of the statements made. These include: (1) competitive pressures, (2) changes in economic conditions in the United States and abroad and the cyclical nature of our markets, (3) loss of distributors, (4) the ability to develop new products and respond to customer needs, (5) risks associated with international operations, including currency risks, (6) accuracy of estimated forecasts of OEM customers and the impact of the current global economic environment on our customers, (7) risks associated with a disruption to our supply chain, (8) fluctuations in the costs of raw materials used in our products, (9) product liability claims, (10) work stoppages and other labor issues, (11) changes in employment, environmental, tax and other laws and changes in the enforcement of laws, (12) loss of key management and other personnel, (13) changes in pension and retirement liabilities, (14) risks associated with compliance with environmental laws, (15) the ability to successfully execute, manage and integrate key acquisitions and mergers, (16) failure to obtain or protect intellectual property rights, (17) risks associated with impairment of goodwill or intangibles assets, (18) failure of operating equipment or information technology infrastructure, (19) risks associated with our debt leverage and operating covenants under our debt instruments, (20) risks associated with restrictions contained in our Convertible Notes and Credit Facility, (21) risks associated with compliance with tax laws, (22) risks associated with the global recession and volatility and disruption in the global financial markets, (23) risks associated with implementation of our new ERP system, (24) risks associated with the Bauer and Lamiflex acquisitions and integration and other acquisitions, (25) risks associated with the Company’s investment in a new manufacturing facility in China, and (26) other risks, uncertainties and other factors described in the Company’s quarterly reports on Form 10-Q and annual reports on Form 10-K and in the Company’s other filings with the U.S. Securities and Exchange Commission (SEC) or in materials incorporated therein by reference. Except as required by applicable law, Altra Holdings, Inc. does not intend to, update or alter its forward looking statements, whether as a result of new information, future events or otherwise. AIMC-E

Contact:

Altra Holdings, Inc.

Christian Storch, Chief Financial Officer

781-917-0541

Christian.storch@altramotion.com