Ilgauskas told the Cleveland Plain Dealer on Friday that it's time for him to walk away.
"Enough is enough," Ilgauskas said. "My body is beat up and I'm tired physically. There is no age limit, but everyone knows when it's time."
Ilgauskas played his first 12 NBA seasons in Cleveland after the Cavaliers picked him No. 20 overall in the 1996 draft. He owns team records for games played, rebounds, blocks and is second in team history with 10,616 points, according to the paper.
"I want to spend more time with my family," Ilgauskas, 36, told the paper. "I have spent the past 15 years living out of a suitcase. It's time."
He averaged 5.0 points and 4.0 rebounds last season for the restructured Heat, both career lows, and exercised his $1.4 million option for the 2011-12 season in June before the lockout started.
Ilgauskas, who was born in Lithuania, told the paper that he will always think of Cleveland as his home.