The Syrian news agency SANA says Carl Campeau was handed over to a UN official in Damascus by the Foreign Ministry.
UN spokesman Martin Nesirky says initial indications are that Campeau is in good health.
The Syrian government says Campeau escaped his captors.
Campeau was reportedly captured when 21 Filipino UN workers were detained by rebels in February near the ceasefire line between Israeli-occupied Golan Heights and Syria.
The others were freed three days later.
Canada officially withdrew its contingent from the peacekeeping force on the Syrian border in September 2012.
Campeau was a legal adviser to the observer force, which was set up after the 1973 Yom Kippur War.
"We are thrilled at the news that Carl Campeau has been released in Syria," said Jean-Bruno Villeneuve, a Foreign Affairs spokesman.
"Our ambassador to Lebanon has already spoken with him and we are offering him whatever support he requires .... His ordeal is a reminder to all Canadians of the incredibly dangerous situation in Syria. Canada continues to advise Canadians to avoid all travel to Syria."
"I was held prisoner for eight months," Campeau, a legal adviser to the UN Disengagement Observer Force, said on Syrian television.
Campeau said he fled the house where he was being held when his captors neglected to lock the door.