Team USA managing director Jerry Colangelo said Durant reached out to him and coach Mike Krzyzewski on Thursday afternoon and "expressed that he is just physically and mentally drained from the NBA season and his attention to his many responsibilities."
Durant had participated in the Americans' training camp in Las Vegas last week.
"This was an extremely difficult decision as I take great pride in representing our country," Durant said in a statement. "I know that I owe it to my USA Basketball teammates to be totally invested in the experience. After going through training camp with USAB, I realized I could not fulfill my responsibilities to the team from both a time and energy standpoint.
"I need to take a step back and take some time away, both mentally and physically in order to prepare for the upcoming NBA season. I will be rooting for USAB and look forward to future opportunities with them."
His withdrawal comes less than a week after Indiana's Paul George was lost to an open tibia-fibula fracture and follows previous withdrawals by All-Stars Kevin Love, Blake Griffin and LaMarcus Aldridge, and NBA Finals MVP Kawhi Leonard.
Durant was the MVP of the world championship in 2010, leading the Americans to that title for the first time since 1994. The Oklahoma City star also started on their gold-medal-winning team in the 2012 Olympics.
That leaves 15 finalists for Team USA, which is scheduled to resume preparations for the FIBA World Cup on Aug. 14 in Chicago.
USA's odds to win went from 2-7 to 2-5, while Spain's went from 5-2 to 2-1, according to the Las Vegas Superbook. All other odds remained the same.
"He tried to give it a go at our recent Las Vegas training camp but felt coming out of camp that he was not prepared to fulfill the commitment he made to the team," Colangelo said in a statement. "Coach K and I fully support Kevin. His well being is the most important thing to us and we support him taking the time to get ready for next season.
"He's been part of the National Team program for eight years and a big part of the success we have achieved, and we look forward to him being part of our success in the future as well."
The FIBA World Cup, featuring 24 national teams, is scheduled to be held Aug. 30-Sept. 14 in Spain.
The Associated Press contributed to this report.