 In late 1979, Mentzer won the heavyweight class of the Mr. Olympia, again with a perfect 300 score, but he lost in the overall to Frank Zane who was awarded the title for a third time that year.In the 1980 Mr. Olympia he placed fourth (in a tie with Boyer Coe) behind Arnold Schwarzenegger, Chris Dickerson and Frank Zane.He retired from competitive bodybuilding after that show at the age of 29.