Delgado, who played for the Toronto Blue Jays, Florida Marlins and New York Mets during a 17-season career, has not played in the majors since he suffered a season-ending injury to his right hip in May 2009.
"There comes a moment when you have to have the dignity and the sense to recognize that something is not functioning," Delgado, 38, said at a news conference in his native Puerto Rico. "You can't swim against the current."
Delgado, who had 11 seasons with 30 or more home runs, retires with a .280 career batting average, 1,512 RBIs and 473 homers. His best season came with Toronto in 2003 when he hit .302 with 42 home runs and 145 RBIs.
He remains Toronto's all-time leader in several offensive categories, including home runs (336) and RBIs (1,058).
(Reporting by Gene Cherry in Salvo, North Carolina; Editing by Frank Pingue)