The phone company hasn't used Woods' image extensively in advertising, but its logo appeared on his golf bag. That deal had been billed as a "multiyear" agreement when it was signed early in 2009, after Buick ended its endorsement one year early because of its financial woes.
Woods has also been the host of the AT&T National PGA Tour event since it started in 2007. Tour spokesman Ty Votaw said that since Woods is on indefinite leave from professional golf, he will not serve as host for the 2010 event. However, his Tiger Woods Foundation will continue to be the beneficiary of the AT&T National, under a contract that runs through 2014, Votaw said.
AT&T said it would continue to sponsor the event.
Woods won the 2009 AT&T National in July at the Congressional Country Club in Bethesda, Md. The AT&T National is moving to Aronomick Country Club outside Philadelphia the next two years as Congressional prepares to host the 2011 U.S. Open.
AT&T has also been the presenting sponsor of the annual Tiger Jam concert event in Las Vegas.
AT&T, which is based in Dallas, did not comment on its reasons for dropping Woods, or how much the relationship was worth.
Woods' agent, Mark Steinberg, had no comment on AT&T's decision.
Consulting firm Accenture dropped the athlete two weeks ago, saying he was "no longer the right representative" of the company's values.
Gillette, a unit of the Procter & Gamble Co., also has said it won't air ads for its razors that include Woods or include him in public appearances.
Swiss watch maker Tag Heuer, a unit of luxury goods empire LVMH Moet Hennessy Louis Vuitton, also said that it would "downscale" its use of golfer Tiger Woods' image in its advertising campaigns for the foreseeable future.
Electronic Arts Inc., which puts out the "Tiger Woods PGA Tour" series of golf video games, has not said what its plans are for the franchise. The company did not immediately return requests for comment Thursday. Nike Inc. and PepsiCo Inc.'s Gatorade are other big sponsors that haven't severed their ties.
AP Golf Writer Doug Ferguson in Honolulu contributed to this report.