Dreier made the announcement Wednesday. He called himself a "proud institutionalist" and said Congress is as great as it has ever been.
Redistricting in California has made races tough for several incumbents. Three other longtime Republicans -- Jerry Lewis, Wally Herger and Elton Gallegly -- have announced plans to retire. Dreier's decision had been expected based on new congressional lines.
All total, 21 Democrats and 16 Republicans in the House have announced that they would retire or seek another office.
Dreier said he had considered leaving three years ago but chose to return to focus on cutting spending, getting free trade bills passed and enhancing national security.
