AT&T shares rose 4 percent in premarket trade to $26.35 after the news.
The biggest U.S. telecommunications company said profit fell to $3.13 billion, or 53 cents per share, from $3.46 billion, or 57 cents a share, a year earlier.
Analysts on average had expected 48 cents per share, according to Reuters Estimates.
Revenue fell to $30.57 billion from $30.74 billion. Analysts on average were expecting $31.06 billion.
The company, which trails Verizon Wireless in mobile phone customers, said it added 1.2 million cell phone customers in the quarter, in line with the average forecast of five analysts contacted by Reuters.
(Reporting by Sinead Carew; editing by John Wallace)