Ward's decision came amid critical media reports in recent days that raised more questions about his management and ethics, from the almost $28,000 spent on his wife's travel by the USOC to allowing his homebuilder to buy tickets to the Salt Lake Olympics through the USOC.
The fact that he had a membership at the controversial Augusta National Golf Club, which excludes women, did not help.
There also was constant pressure from Sen. Ben Nighthorse Campbell (R-Colo.), who visited USOC headquarters in Colorado Springs, Colo., Friday.
Campbell often urged Ward to give up his post, saying Friday that he wasn't the only chief executive who had been problematic for the USOC, but that he had brought controversy "to an art form."
Campbell also said that if Ward and some of his closest associates resigned, "a lot of the problems would go away in the eyes of the Senate."
He has partnered with Sens. Ted Stevens (R-Alaska) and John McCain (R-Ariz.) to reform the USOC.
Ward was the eighth high-ranking official of the organization to resign in recent months. Among others were former CEO Norman Blake, and Presidents Marty Mankamyer and Sandra Baldwin.
"In the hope that we can shift the focus back to the athletes and the ideals of the Olympic movement, I have decided to resign," Ward said in a prepared statement, "with the deeply ingrained belief that I have served the USOC and the Olympic movement constructively and with integrity."
The Denver Rocky Mountain News reported Sunday that Acting President Bill Martin will try to name an interim CEO this week. The paper said names that have cropped up among some Olympic officials include former USOC President Bill Hybl and Fraser Bullock, the No. 2 man in charge of the highly successful 2002 Salt Lake Olympics.