Purpose: In common with most standardized admissions tests, the Medical College Admission Test (MCAT) scores disproportionately screen out applicants from disadvantaged and underrepresented minority groups, relative to their demographic importance. The impact of programs to prepare students for the MCAT has not been adequately addressed. The purpose of this study was to evaluate the direct effect of an intensive preparation program for the MCAT on student cognitive achievement. Method: Using an outcomes research design, the pre- and post-program performance of four cohorts of 88 participants was compared. Primary outcomes were MCAT performance on the Physical Sciences, Verbal Reasoning, Writing Sample and Biological Sciences sections. Data was collected and analyzed with descriptive and inferential statistics. Results: There was significant difference between the pre and post program performance of the 88 participants in the Physical Sciences, Verbal Reasoning, and Biological Sciences sections of the MCAT. In general, performance in the science-based sections (Physical Sciences and Biological Sciences) of the MCAT dramatically exceeded the scores reported for the non-science sections (Verbal Reasoning and Writing Sample) of the test. Analysis of variance showed no significant difference in performance of the four study cohorts suggesting their homogeneity. Conclusions: The cognitive gains achieved by study participants strongly suggest the effectiveness of our MCAT Preparation Program. Improved student performance in the program may be attributed to contextual, behavioral and motivation factors that may be basis of a future research study. (Contains 5 tables.)