The Peruvian, who will be 38 in October, is in his third spell at Werder after also playing twice for Bayer Munich as well as Chelsea.
"I feel very good and look forward to another year playing for the club," he said in a statement. "This was a tough season but also an amazing one for me. I hope we can finish in a better position next season."
Pizarro was the club's top scorer with 14 league goals this season after joining in September from Bayern. Werder secured their Bundesliga spot with a last-gasp 1-0 victory over Eintracht Frankfurt on Saturday.
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"We are very happy that Claudio, as a leading player with all his experience, will be part of the team next season as well," said Werder sports director Thomas Eichin.
The striker is the Bundesliga's all-time top foreign scorer with 190 goals in 411 league matches and also leads Werder's scorers' list with 103 goals in 187 league appearances.
(Reporting by Karolos Grohmann; Editing by Ian Ransom)
