The Longueuil, Que., native originally joined the Canadian sledge team as a forward in 2004 before moving to the goaltender position. He finishes with a 39-5-1 record over 51 career appearances with the national team.
"It has been a memorable 10 years, getting to represent my country and travel the world playing the game I love," St-Amand said in a release. "I cannot thank my teammates, coaches and Hockey Canada enough for giving me every opportunity to succeed. Now feels like the right time to step away, try new things and spend more time with my family."
St-Amand, 36, played in three Paralympic Winter Games. In addition to his gold from Turin in 2006, he won bronze earlier this year in Sochi and played on the team that finished fourth in 2010 at Vancouver.
St-Amand won world championship gold in 2008 and 2013, adding bronze medals in 2009 and 2012.