Physician's Assistants (P.A.), recent additions to the health profession, have proved valuable as "extenders" for primary physicians in relatively remote rural areas. More specialized surgical assistants have been trained for the community-practicing surgeon. The introduction of physician's assistants into university centers has been proceeding at a slower pace. A need has existed for an accurate assessment of the role of the P.A. in a residency-training program. In subspecialties, such as pediatric surgery and thoracic surgery, an increasing patient load has usually required a corresponding increase in junior resident staff. This resident coverage is usually dependent upon the availability of general surgical house staff since pediatric surgical trainees are currently fixed in number. Foreign medical graduates are no longer available in large numbers and general surgical programs themselves are being reevaluated and the number of trainees decreased. In this setting physician's assistants can be used to augment patient coverage by acting as junior surgical residents.