Anna Kibor, 48, of Kenya hasn't run a marathon in two years after recovering from a knee injury but has won the women's title in the 2012 Manitoba Marathon.
Kibor crossed the finish line at the University of Manitoba Stadium with an unofficial time of 2:49.45.
"I'm very happy," said the 48-year-old Kibor from Kenya.
The victory marks the first race in 2 years for Kibor - a break as the result of injury.
"I felt good out there. My injuries are fully recovered," she said.
Kibor arrived in Winnipeg on Wednesday after the race was recommended by a friend.
Nadyia fry was the second women to cross the line in the full marathon with a time of 2:51:14 and Cathy Cullen placed third with a time of 2:54:37.