Petitclerc competed in the Paralympic Games for the first time in Barcelona in 1992, returning with two bronze medals, the start of collection that now includes twenty one Paralympic medals, fourteen of them gold. Four years later, at the Atlanta games, she took gold medals in the 100 and 200 m events and three silvers in the 400, 800, and 1500 m races. At the 2000 Summer Paralympics, she won two golds, in the 200 m and 800 m, and two silvers, in the 100 m and 400 m races. She won three gold medals (in 100 m, 200 m, and 400 m) and a bronze (800 m) at the 2002 World Championships and a gold at the 2002 Commonwealth Games in the 800 m. At the 2004 Summer Olympics (where wheelchair racing was an exhibition sport) she won the 800 m, and went on to an impressive showing with 5 gold medals at the 2004 Summer Paralympics. When she returned from Athens in 2004, Petitclerc told reporters the 2008 Summer Paralympics in Beijing would be her last big international meeting but that she will continue training and road racing for a while. For her performance in 2008, she was awarded the Lou Marsh Trophy as Canadian athlete of the year and the Canadian Press's Bobbie Rosenfeld Award as Canada's female athlete of the year. Petitclerc was also awarded the Best Female award at the Paralympic Sport Awards.