In a study of the relative contribution of two achievement measures and five aptitude measures in determining three measures of academic performance, an achievement measure in combination with an aptitude measure provided the most efficient explanations. Stepwise multiple regressions were performed on data from 112 medical technology graduates to determine that science grade point average (GPA) and Nelson-Denny Combination sub-score significantly predicted professional GPA. Additionally, science GPA and the Otis Test score explained the variations in both certification examination performance and comprehensive examination performance.