Sources familiar with the situation told the Associated Press that the IOC sent a letter to Armstrong on Wednesday night asking him to return the medal. The move came after the IOC was notified by cycling's governing body that Armstrong had not appealed the decision to disqualify him.
The news comes on the same day Armstrong's "no-holds barred" interview with Oprah Winfrey is set to air.
In a text message sent to the Associated Press leading up to the interview, Armstrong said, "I left it all on the table with her and when it airs the people can decide. I have no idea what the future holds other than me holding my kids."
Armstrong's interview is set to air in a two-part special starting Thursday night on the Oprah Winfrey Network.
The Associated Press contributed to this report.