How many movies have Mohammed Rafi and O.P. Nayyar collaborated on?

They have worked on 5 movies together! Their first movie together was Mr. & Mrs. '55 (1955) while their highest rated movie together was Yeh Raat Phir Na Aaygi (1966). They have not worked together since Yeh Raat Phir Na Aaygi (1966). They are most known for their drama films together.