LAS VEGAS — Former heavyweight champion John Ruiz is retiring.

The 38-year-old boxer said in a statement today he's leaving after an 18-year career. He was the WBA champ two times and finished with a record of 44-9-1, including 30 knockouts.

Ruiz was knocked down four times in a loss to David Haye this month. He hit the canvas twice in the first round, and his trainer ended the fight in the ninth.

Ruiz defeated three world champions — Evander Holyfield, Hasim Rahman and Tony Tucker. He fought in 12 championship bouts and became the first Latino heavyweight champion.

He plans to move his family from Las Vegas to his home in the Boston area and open a boxing gym in the city.