Clendenon did not appear in the Mets' 1969 National League Championship Series three-game sweep of the Atlanta Braves. In the 1969 World Series against the Baltimore Orioles, Clendenon appeared in four of the five games, missing only Game 3. He went 2 for 4 in Game 1, scoring the Mets' only run in their 4–1 loss. He hit a fourth-inning home run in game two and a second-inning home run in game four to give the Mets early 1–0 leads in both games.