David Letterman’s Most Frequent Guests 

Late Show:
Regis Philbin: 136
Jack Hanna: 75
Tony Randall: 70
Marv Albert: 53
Tom Brokaw: 49

Late Night:
Marv Albert: 73
Richard Lewis: 48
George Miller: 40
Tom Brokaw: 40
Jay Leno:39
Teri Garr: 30
Robert Klein: 30