"I've made my decision to move back to Russia and play in the KHL," Markov said on Thursday.
Markov, 38, was the longest-tenured player on the team and an alternate captain last season. The two-time All-Star had six goals and 36 points and was plus-18.
"On behalf of the entire organization, I would like to thank Andrei for his great contributions during his 16 seasons as a proud member of the Montreal Canadiens," team president and CEO Geoff Molson said in a statement. "Arguably one of the best defensemen in franchise history, Andrei was a model of dedication to the great game of hockey. A respected figure around the league and among his teammates,
"Andrei demonstrated leadership both on and off the ice. Andrei's commitment to our franchise was second to none, proven by his overcoming three serious and potentially career-ending injuries. I would like to wish Andrei the best of luck in the next step of his career, and happiness with his family."
Markov was taken in the sixth round of the 1998 draft by Montreal after establishing himself in Russia. Since playing 14 games in the AHL in 2000-01, he has been a consistent presence on Montreal's blue line.
"I've always been treated well," Markov said. "I'm proud to have been a Canadiens player for 16 years."
Markov is coming off a three-year deal that carried a $5.75 million salary-cap hit last season. When the Canadiens signed veteran defenseman Mark Streit this week, it appeared that Markov was out of their plans.
"I didn't see myself with any other NHL team," Markov said. "I didn't see myself wearing another jersey."
In February, Markov brought his twin sons from Russia to Montreal after their mother and his former partner died of cancer. Earlier this month, Markov married Sonya Sonechka in Russia, and the ceremony was attended by former teammate P.K. Subban.