New York announced the move Thursday, a week after Beltran departed without managing a game. Rojas, who had been the Mets' quality-control coach, was given a multiyear contract.
"I will work tirelessly to help this team win," Rojas said in a statement. "I believe this team and coaching staff can do special things, and I look forward to working together with everyone to reach our goals."
Rojas became New York's fourth manager in the past 2½ years -- and third in four months. He is to be introduced Friday at a Citi Field news conference.