Nov. 5 (Bloomberg) -- AT&T Inc.’s $945 million purchase of Centennial Communications Corp. won final regulatory approval from the Federal Communications Commission.

The deal, which would add 1.1 million wireless customers to the second-largest U.S. mobile-telephone company, was approved on a 5-to-0 vote, the agency said today on its Web site. They FCC said it placed conditions on its approval.

AT&T agreed to pay $8.50 a share and to take on about $2 billion in debt for Wall, New Jersey-based Centennial. AT&T and Verizon Wireless, the biggest U.S. mobile-phone service, are expanding through acquisitions as subscriber growth slows, with more than four-fifths of the U.S. population already using a wireless device.

An AT&T spokesman, Michael Balmoris, declined to comment. A message left after regular business hours for Centennial’s spokesman, Steve Kunszabo, wasn’t immediately returned.

Centennial has wireless customers in Puerto Rico and rural areas in the U.S. Midwest and Southeast. The Justice Department approved the deal Oct. 13 and said the combined company must sell assets in Louisiana and Mississippi.

The FCC said its conditions included the divestitures required by the Justice Department, and commitments offered by the companies. Among those are a pledge by AT&T to limit contact with America Movil SAB, Latin America’s largest mobile phone company, and a competitor to AT&T and Centennial in Puerto Rico.

AT&T also must honor agreements that other companies struck to complete telephone calls over Centennial’s network, the FCC said. AT&T today told FCC staff it could provide advanced services to Centennial customers, according to a disclosure filing.

Centennial was unchanged at $8.46 in Nasdaq Stock Market trading. AT&T rose 41 cents to $25.94 at 4 p.m. in New York Stock Exchange composite trading.

The cash price for the deal is based on 111.16 million Centennial shares outstanding on Oct. 5.

To contact the reporter on this story: Todd Shields in Washington at tshields3@bloomberg.net

Last Updated: November 5, 2009 19:23 EST