OBJECTIVE To evaluate the effect of residency program merger on third-year medical student clerkships using student evaluations of their experiences and standardized subject examination scores. METHODS End-of-clerkship ratings from student evaluations and National Board of Medical Examiners standardized subject examination scores in obstetrics and gynecology were used from clerkship sites where three separate military residency programs in obstetrics and gynecology recently merged into two new programs. Mean student evaluation scores and subject examination scores for the year preceding and the year following the merger were compared. RESULTS The mean differences in medical student evaluation scores before and after merger of the residency programs were 0.1 (Mann-Whitney rank sum, P = .1), -0.1 (Mann-Whitney rank sum, P = .8), and 0.2 (Mann-Whitney rank sum, P = .3). The mean differences for subject examination scores before and after merger of the residency programs were -3.5 (95% confidence interval [CI] -33.2, 26.2; paired t test), -30.1 (95% CI -58.9, -1.4; paired t test), and -35.3 (95% CI -74.8, 4.3; paired t test). CONCLUSION Merger of residency programs in obstetrics and gynecology does not appear to have a deleterious effect on medical students' satisfaction with the clerkship or their performance on standardized subject examinations at our institution.