His resignation comes following a number of media reports which questioned his management and ethics and mounting political pressure.
With the New York bid for the 2012 Games still perceived by many as the favourite to win the hosting race, the politics within USOC are in disarray.
Ward is the eighth senior figure to quit the organisation in the last two years.
Said Ward in a statement: “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.
"With the deeply ingrained belief that I have served the USOC and the Olympic movement constructively and with integrity."
An interim replacement is due later this week.
The crisis engulfing the United States Olympic Committee continues after Lloyd Ward dramatically quit the organisation at the weekend as its chief executive officer.
