OBJECTIVE: To examine the effects of a primary-care weight management intervention on physical activity (PA) among overweight/obese women. METHODS: This randomized controlled trial included 139 women (92% African American). The effects of a physician-delivered tailored intervention were compared with standard care. Repeated measures analyses of variance (ANOVA) were used to examine changes in PA (measured by a 7-day physical activity recall) and physical fitness (measured by heart rate recovery following exercise). RESULTS: Although the intervention group demonstrated an increase in PA, this did not differ significantly from standard care. A significantly greater proportion of intervention participants (90%) achieved current PA recommendations compared with standard care (77%), P<.03. CONCLUSION: These results provide novel information suggesting that a physician-delivered intervention may have limited effectiveness for increasing PA among this at-risk population.