He was sentenced to six years in jail in a trial that concluded in October.
Khaidarov's release coincided with talks Uzbek Foreign Minister Vladimir Norov had with European Union officials in Brussels.
The EU is to decide on November 13 whether to extend sanctions imposed on Uzbekistan following a military crackdown in Andijon in May 2005. Those sanctions include a weapons embargo and a ban on travel for a handful of officials implicated in the violence.
Khaidarov told RFE/RL's Uzbek Service from his hometown that he will continue his work as a journalist but that he first needs to restore his health, which he said deteriorated during his stay in jail.
"I got very thin [in jail]," he said. "Within a short period of time, I lost probably about 12 kilograms. In jail we had to do compulsory exercises from 5:00 in the morning until 10:00 in the evening. Maybe it's because of this, because my organism was not used to those conditions, I now feel pains in my bones and head."
Khaidarov was arrested in Jizzakh on September 14 on extortion charges that he denies.
He was sentenced on October 5 after a trial that Western rights groups condemned as a "parody of justice."