NEW YORK (Reuters) - AT&T Inc reported faster-than-expected wireless subscriber growth for the first quarter, driven by sales of tablet computers with cellular connections.

The No. 2 U.S. mobile service added 296,000 subscribers in the quarter compared with Wall Street expectations for just over 195,000, according to six analysts contacted by Reuters.

This included a net addition of 365,000 subscribers using tablet computers, implying a net loss of 69,000 phone subscribers.

The company reported a wireless service margin of 43.2 percent based on earnings before interest, tax, depreciation and amortization, up from 42.3 percent in the year-ago quarter and beating the six analysts' expectations for 42.3 percent.

Its profit rose to $3.7 billion, or 67 cents per share, from $3.58 billion, or 60 cents per share, in the year-ago quarter.

Revenue fell to $31.36 billion from $31.82 billion in the year-ago quarter before it sold its telephone directory business. Analysts, on average, had expected revenue of $31.74 billion, according to Thomson Reuters I/B/E/S.

AT&T shares fell 2 percent to $38.15 in late trade after closing at $39 in the regular New York Stock Exchange session.

(Reporting By Sinead Carew; editing by Jim Marshall)