Maynard, 27, has had an injury-plagued career, and has two games to his name after joining the Demons as a Category B rookie in 2017.
He made his debut in round 20, 2017 against the Giants, before facing the Cats in round one in 2018.
“It’s really unfortunate for Corey, as he just hasn’t been able to have a clear run at it recently,” General Manager of Football Operations Josh Mahoney told Melbourne Media.
“The impact Corey has had on the club should not be measured by the number of games he has played. His leadership, professional attitude and care for the club has had a major influence on his teammates.
“His commitment has been sensational over the past three seasons.”
Maynard’s hip injury early in 2018 has hampered his career, as he hasn’t fully recovered from that injury.
“I’m really comfortable with the decision I’ve made to retire from the game,” Maynard told the club’s website.
“Obviously I’m bitterly disappointed with how things have panned out for me from a physical standpoint over the past 18 months.
“The game doesn’t owe you anything and unfortunately my hip can no longer meet the demands of the AFL game.
“I knew changing sports at the age of 25 was going to be a challenge, but that was a risk I was prepared to take.”