In view of the new residency guidelines, which restrict resident work hours, the use of physician assistants (PAs) for patient care continuity during off-hours of residents may become a common practice. The purpose of this study was to assess the quality of patient care during transition from resident- to PA-assisted trauma program (without residents) and comparative simultaneous support. A retrospective analysis of patient care during two 6-month segments was carried out: during resident-assisted program at a level II trauma center in 1998 and a PA-dedicated trauma program in 1999. With reinvolvement of senior surgical residents, a focused analysis for the last quarter of 2002 was done. Regression analysis indicated the only statistically significant outcome was decreased length of stay (LOS) when patients were transferred directly from emergency center (EC) to floor in 1999. The mean LOS was 2.54 +/- 4.65 compared to 3.4 +/- 5.81, and no statistical difference in other assessments was noted. Focused analysis in 2002 showed 100 per cent participation of PAs during the trauma alert compared to 51 per cent by residents. Substitution of residents with PAs had no impact on patient mortality; however, LOS (from EC to floor), was statistically reduced by 1 day. Trauma programs can benefit with collaboration of residents and PAs in patient care.