The purpose of this study was to compare the Physician Assistant Clinical Knowledge Rating and Assessment Tool (PACKRAT) and the Objective Structured Clinical Examination (OSCE) as predictors of performance on the Physician Assistant National Certifying Examination (PANCE). To become a physician assistant (PA) one must graduate from an accredited program and pass the PANCE. Due to the fact that the PACKRAT and the OSCE are being used to evaluate and prepare students to take the PANCE, it is imperative to know the predictive value of these exams on the PANCE. Methods: The data were collected on 84 WSU PA Program graduates of 2003 and 2004 who had taken the PANCE. The identified set of explanatory variables used included PACKRAT I and II, OSCE I and II, and PANCE scores. Correlation analysis was conducted comparing PACKRAT I, PACKRAT II, OSCE I, and OSCE II to PANCE using linear models to determine how the scores relate. Results: PACKRAT and PANCE scores were shown to be highly correlated. OSCE and PANCE scores were correlated, but to a lesser degree. Linear regression revealed a relationship between the PACKRAT and PANCE (P<0.05) as well as the OSCE and the PANCE (p<0.001). Conclusion: Both the PACKRAT and OSCE scores were predictive of PANCE scores. The PACKRAT was more predictive of the PANCE than the OSCE.