The objective of this study was to determine the effect of a vertically integrated curriculum intervention on the geriatric knowledge and performance in clinical skills of third-year medical students. This observational cohort study conducted at the University of Michigan Medical School evaluates the performance of 622 third-year medical students from the graduating class years of 2004 through 2007. An integrated curriculum intervention was developed and implemented for the class of 2006. Its elements included identification and tracking of geriatric learning outcomes in an individualized Web-based student portfolio, integration of geriatric content into preclinical courses, development of a geriatric functional assessment standardized patient instructor, and an experience in a geriatrics clinic during the ambulatory component of the third-year internal medicine clerkship. Medical student performance was assessed on a geriatric knowledge test and during a geriatric functional assessment station administered during an Observed Structured Clinical Examination (OSCE) at the beginning of the fourth year. Student performance on the geriatric functional assessment OSCE station progressively improved from pre-intervention performance (mean performance+/-standard deviation 43+/-15% class of 2005, 62 + 15% class of 2006, 78+/-10% class of 2007; analysis of variance, P<.001). Similarly, student performance on the geriatric knowledge test was significantly better for the classes of 2006 and 2007 than for the class of 2005 (model F ratio=4.72; P<.001). In conclusion, an integrated approach to incorporating new educational geriatric objectives into the medical school curriculum leads to significant improvements in medical student knowledge and in important clinical skills in the functional assessment of older patients.