Exhibit 99.1

Primus Telecommunications Group, Incorporated

Reports First Quarter 2012 Results

MCLEAN, VA – (MARKET WIRE) – May 10, 2012 – Primus Telecommunications Group, Incorporated (PTGi) (NYSE: PTGI), a global facilities-based integrated provider of advanced telecommunications products and services, announced results for the first quarter ended March 31, 2012. PTGi completed the acquisition of Arbinet Corporation on February 28, 2011; therefore, first quarter 2012 comparisons are not directly comparable with prior periods.

Consolidated Results

Net revenue for the first quarter 2012 was $234.7 million, an increase of 8.2% from first quarter 2011 net revenue of $217.0 million. Contributing to the increase in net revenue was a 4.9% increase in net revenue from growth services (broadband, data center, SME VoIP, and other data services). Total company data center revenue of $10.6 million increased 9.1%. Specifically, Primus Canada’s data center revenue increased 10.1% to $8.2 million in the first quarter, while construction of the new 30,000 square foot Toronto Tier III facility accelerates toward a targeted third quarter grand opening.

Adjusted EBITDA was $20.0 million, an increase of 10.7% from first quarter 2011 Adjusted EBITDA of $18.1 million; first quarter 2012 Normalized Adjusted EBITDA was $22.9 million. The year-over-year impact of foreign exchange translation was an increase of $1.2 million to revenue for the first quarter 2012 and an increase of $0.3 million to Adjusted EBITDA. Free Cash Flow in the quarter was $9.9 million compared to Free Cash Flow of $9.6 million in first quarter 2011.

Peter D. Aquino, Chairman, President and Chief Executive Officer, stated, “PTGi’s rapid pace of change is playing out in a two-pronged strategy, first, improving operations and focusing on profitable growth in high-ROI projects, such as our data center opportunity in Canada, and second, yielding a successful outcome of our strategic review. By the time of our first quarter report, we delivered on both fronts, and are very excited about the transformation of the new PTGi. The pending sale of Primus Australia is a significant liquidity event and is a catalyst to create three separate operating segments going forward led by our Canadian team: a “pure play” data center business unit; a North American telecom unit focused on consumer, SME, and carrier voice and data services, including U.S. Retail; and our ICS operation. This completes a portfolio of assets primarily located in North America. With the consolidation and realignment, we also expect corporate overhead annual run-rate savings of over $7 million, all part of a strategy to continue to deliver value to shareholders.”

Key First Quarter 2012 Accomplishments

Canada:

First Quarter 2012 Detail

Canada Revenue – Net revenue of $57.9 million decreased 4.8% as compared with first quarter 2011. The impact of foreign currency translation was a decrease of $0.9 million. On a constant currency basis, net revenue decreased 3.3% as declines in retail long distance, prepaid services and local services were partially offset by increases in broadband, data center, and SME VoIP.

Australia Revenue – Net revenue of $70.1 million decreased 2.2% from $71.7 million in first quarter 2011. The impact of foreign currency translation was an increase of $3.3 million. On a constant currency basis, net revenue decreased 6.9% as decreases in traditional voice, DSL, broadband, and wholesale services were partially offset by increases in data VPN services and wireless services.

International Carrier Services Revenue – Net revenue of $96.6 million increased 32.2% from $73.0 million in first quarter 2011, primarily due to the integration of Arbinet. The impact of foreign currency translation was a decrease of $1.2 million.

U. S. Retail Revenue - Net revenue of $10.1 million decreased 9.7% from $11.2 million in first quarter 2011, primarily due to decreases in residential voice services.

Net revenue less cost of revenue was $72.2 million, or 30.8% of net revenue, compared to $70.1 million, or 32.3% of net revenue, in first quarter 2011. On a constant currency basis, net revenue less cost of revenue increased primarily due to the inclusion of Arbinet and an increased contribution of higher-margin data center revenue in the mix. The impact of foreign currency translation was an increase of $0.9 million.

Selling, general and administrative (SG&A) expense was $53.9 million, or 23.0% of net revenue, compared to $53.1 million, or 24.5% of net revenue in first quarter 2011. The leveraging of SG&A is largely due to effective cost management throughout the company. The impact of foreign currency translation was an increase of $0.6 million.

Income from operations was $2.9 million compared to a loss from operations of $12.7 million in the first quarter 2011. First quarter 2011 operating loss includes a $14.7 million impairment charge to goodwill related to the Arbinet acquisition.

Adjusted EBITDA was $20.0 million, or 8.5% of net revenue, compared to $18.1 million, or 8.3% of net revenue, in the first quarter 2011. Normalized for severance, integration and other non-recurring costs, Adjusted EBITDA was $22.9 million, or 9.8% of net revenue, compared to $19.8 million, or 9.1% of net revenue in the first quarter of 2011.

Net loss was $6.9 million, or $(0.50) per basic and diluted common share, compared to net loss of $19.3 million, or $(1.73) per basic and diluted common share in the first quarter 2011. The number of shares outstanding used to calculate basic and diluted earnings per common share in the first quarter of 2012 was 13.7 million compared to 11.1 million for basic and diluted earnings per common share in the first quarter of 2011.

Balance Sheet, Liquidity and Capital Resources

PTGi ended the first quarter 2011 with $46.2 million in cash and cash equivalents, up from $41.1 million at December 31, 2011. Cash was generated during the first quarter in the following amounts: $20.0 million of Adjusted EBITDA offset, in part, by the usage of $8.1 million for capital expenditures, $1.8 million in capital lease payments, $2.0 million of fees associated with the 2011 debt exchange, $2.2 million paid for taxes and $0.8 million of other expenses. PTGi’s long-term debt, including current obligations, as of March 31, 2012 was $247.6 million, down from $249.3 million as of December 31, 2011.

Free Cash Flow in the first quarter 2012 was $9.9 million compared to free cash flow of $9.6 million in the first quarter 2011. Net cash provided by operating activities was $18.0 million in the first quarter 2012 compared to $16.0 million in the first quarter 2011. The primary contributors to the increase in free cash flow over the prior

year quarter were a $1.9 million increase in Adjusted EBITDA, offset partially by an increase of $1.7 million in capital expenditures. PTGi defines Free Cash Flow as net cash provided by operating activities less cash used in the purchase of property and equipment.

Ken Schwarz, Chief Financial Officer, stated, “PTGi delivered a solid, consistent financial performance in the first quarter. Pending the sale of our Australian operations, our revised outlook for capital expenditures in 2012 for remaining PTGi operations is $21 million to $26 million, primarily related to Canada data center and highly profitable broadband and IP-based growth opportunities.”

Subsequent Event

Entered into definitive agreement to sell Australian operations to M2 Telecommunications for $AUD 192.4 million, the completion of which represents a significant outcome of the company’s strategic review process.

Conference Call

The Company will hold a conference call on Thursday, May 10, 2012 at 8:30 AM ET. To access the call, please dial 866-305-6438 (toll free) or 706-679-7161 approximately 10 minutes prior to the start of the conference call. The conference call will also be broadcast live over the Internet with an accompanying slide presentation, which can be accessed via the Investor Relations section of PTGi’s web site at www.ptgi.com, and have been made available simultaneous with the issuance of this press release. The webcast and slide presentation will be available for replay for 90 days at www.ptgi.com.

A telephonic replay of this conference call will also be available by dialing 855-859-2056 (toll free) or 404-537-3406 (access code: 71433484) from 11:30 AM ET on May 10, 2012 until midnight ET on May 16, 2012.

About PTGi

PTGi (Primus Telecommunications Group, Incorporated) is a leading provider of advanced communication solutions, including, traditional and IP voice, data, mobile services, broadband Internet, collocation, hosting, and outsourced managed services to business and residential customers in the United States, Canada, and Australia. PTGi is also one of the leading international wholesale service providers to fixed and mobile network operators worldwide. PTGi owns and operates its own global network of next-generation IP soft switches, media gateways, hosted IP/SIP platforms, broadband infrastructure, fiber capacity, and data centers located in Canada and Australia. Founded in 1994, PTGi is headquartered in McLean, Virginia.

Non-GAAP Financial Measures

This release includes certain non-GAAP financial measures as defined under SEC regulations, which include Adjusted EBITDA, Normalized Adjusted EBITDA and Free Cash Flow. As such, they should not be considered as substitutes for the most directly comparable GAAP measures and should not be used in isolation, but in conjunction with these GAAP measures. Reconciliations to the most directly comparable GAAP measures are contained in the tables to this release. Additional information regarding the purpose and use for these non-GAAP financial measures is set forth in our Form 8-K disclosing this press release.

Cautionary Statement Regarding Forward Looking Statements

This press release contains or incorporates a number of “forward-looking statements” within the meaning of Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Securities Exchange Act of 1934, as amended. Such statements are based on current expectations, and are not strictly historical statements. In some cases, you can identify forward-looking statements by terminology such as “if,” “may,” “should,” “believe,” “anticipate,” “future,” “forward,” “potential,” “estimate,” “opportunity,” “goal,” “objective,” “growth,” “outcome,” “could,” “expect,” “intend,” “plan,” “strategy,” “provide,” “commitment,” “result,” “seek,” “pursue,” “ongoing,” “include” or in the negative of such terms or comparable terminology. These forward-looking statements inherently involve certain risks and uncertainties and are not guarantees of performance or results, as well as creation of shareholder value, although they are based on our current plans or assessments which are believed to be reasonable as of the date hereof. Factors or risks that could cause our actual results to differ materially from the results we anticipate include, but are not limited to: (i) continuing uncertain global economic conditions; (ii) significant changes in the competitive environment, including as a result of industry consolidation, and the effect of competition in our markets, including our pricing policies; (iii) uncertainties from our announcement of our exploration and evaluation of strategic alternatives that may enhance shareholder value or our ability to complete any transactions arising out of that evaluation, including the pending divestiture of Primus Australia; (iv) our possible inability to generate sufficient liquidity, margins, earnings per share, cash flow and working capital; (v) our ability to attract and retain customers; (vi) our expectations regarding increased competition, pricing pressures and declining usage patterns in our traditional products; (vii) the effectiveness and profitability of our growth products and bundled service offerings, the pace and cost of customer migration onto our networks, and the successful network platform migration to reduce costs and increase efficiencies; (viii) risks associated with the merger of Arbinet, including but not limited to our ability to realize the anticipated benefits of the merger of Arbinet or the timing associated with any such benefits, or volatility in the volume and mix of trading activity on the Arbinet Exchange; (ix) strengthening of U.S. dollar against foreign currencies, which may reduce the amount of U.S. dollars generated from foreign operating subsidiaries and adversely affect our ability to service our significant debt obligations and pay corporate expenses; (x) our compliance with complex laws and regulations in the U.S. and internationally; (xi) further changes in the telecommunications industry or the Internet industry, including rapid technological, regulatory and pricing changes in our principal markets; (xii) our liquidity and possible inability to service our substantial indebtedness or an occurrence of a default or event of default under our indentures; (xiii) our expectations regarding the timing, extent and effectiveness of our cost reduction initiatives and management’s ability to moderate or control discretionary spending; (xiv) management’s plans, goals, expectations, guidance, objectives, strategies, and timing for future operations, acquisitions, synergies, asset dispositions, fixed asset and goodwill impairment

charges, tax and withholding expense, selling, general and administrative expenses, product plans, performance and results; (xv) management’s assessment of market factors and competitive developments, including pricing actions and regulatory rulings; (xvi) our possible inability to raise additional capital when needed, on attractive terms, or at all; and (xvii) our possible inability to hire and retain qualified executive management, sales, technical and other personnel. Many of these factors and risks are more fully described in our annual report, quarterly reports or other filings with the Securities and Exchange Commission, which are available through our website at www.ptgi.com. Other unknown or unpredictable factors could also affect our business, financial condition and results. Although we believe that the expectations reflected in the forward-looking statements are reasonable, there can be no assurance that any of the estimated or projected results will be realized. You should not place undue reliance on these forward-looking statements, which apply only as of the date hereof. Subsequent events and developments may cause our views to change. While we may elect to update these forward-looking statements at some point in the future, we specifically disclaim any obligation to do so.

Investor Contact:

PTGi

Richard Ramlall, SVP Corporate Development and Chief Communications Officer

703-748-8050

ir@ptgi.com

Lippert/Heilshorn & Assoc., Inc.

Carolyn Capaccio

212-838-3777

ccapaccio@lhai.com

(tables follow)

PRIMUS TELECOMMUNICATIONS GROUP, INCORPORATED

CONSOLIDATED CONDENSED STATEMENTS OF OPERATIONS

(in thousands, except per share amounts)

(unaudited)

PRIMUS TELECOMMUNICATIONS GROUP, INCORPORATED

CONSOLIDATED CONDENSED BALANCE SHEET

(in thousands)

(unaudited)

PRIMUS TELECOMMUNICATIONS GROUP, INCORPORATED

RECONCILIATION OF NET INCOME (LOSS) ATTRIBUTABLE TO PRIMUS TELECOMMUNICATIONS GROUP, INCORPORATED

TO ADJUSTED EBITDA AND NORMALIZED ADJUSTED EBITDA

(in thousands)

(unaudited)

PRIMUS TELECOMMUNICATIONS GROUP, INCORPORATED

RECONCILIATION OF NET CASH PROVIDED BY (USED IN) OPERATING ACTIVITIES

TO FREE CASH FLOW

(in thousands)

(unaudited)