"Never, say never," he said in an interview at the Canadian Space Agency on Monday.
The veteran astronaut is due to launch on a Russian spacecraft with NASA astronaut Tom Marshburn and Russian cosmonaut Roman Romanenko on Dec. 19 — two weeks later than planned.
The three were originally scheduled to blast off from the Baikonur Cosmodrome in Kazakhstan on Dec. 5.
Hadfield says a Russian Soyuz will be visiting the space station in a couple of weeks and that trips by a couple of resupply ships are also planned.
"Until those have gone, we don't know for sure, but right now it's planned for Dec. 19 at about 7 a.m. eastern time," he said.
During Hadfield's lengthy stay, he will become the first Canadian to command the space station. That will happen during the second half of his mission.
But the Canadian astronaut won't confirm it will definitely be his last trip into space.
"If you just look at the natural career of an astronaut, this would be an obvious time that this would be the last flight," he said.
"But I just turned 53 and I'm healthy so let's see what the future brings and what all the things I've learned give me the opportunity to do in the future."
Hadfield may have his eye on a number of commercial space companies like Virgin Galactic, which will take tourists into space for flights 100 kilometres above the Earth's surface.
It hopes to begin its first sub-orbital space flights by 2013.
"Hopefully within the next couple of years, we will have commercial vehicles launching and getting into sub-orbital and someone's gotta fly those vehicles, so, you never know," he said in an interview.
Hadfield's first space trip was in November 1995 when he visited the Russian Space Station Mir. His second voyage was a visit to the International Space Station in April 2001, when he also performed two walks.
Hadfield also hasn't ruled out the possibility of another space walk during his upcoming visit to the giant orbiting laboratory.
He noted there was a recent electrical failure on the space station which could involve replacing the rotating structure that turns the solar panels on the space station.
"We may have a space walk to do and I'd love a chance to walk in space again," Hadfield said.