Background: To determine the feasibility of a 12-week physical activity (PA) intervention guided by social cognitive theory for ethnically diverse endometrial cancer (EC) survivors and to evaluate whether such an intervention might improve PA behavior, physical function, waist circumference, and quality of life. Methods: Out of 119 potential participants contacted via telephone, 54 did not respond, 29 declined, and 6 expressed interest but did not complete baseline testing. 30 obese EC survivors (40% non-Hispanic black, 33% Hispanic, 17% non-Hispanic white) were placed into a PA intervention (INT, n = 15) or wait-list control (CON, n = 15). Group classes consisted of 30 min of behavioral counseling and a 60 min exercise program. CON was assigned to usual care. Participants attended classes 1-2x/week and were provided with a 90 min/week at-home exercise program. The intervention data from each group were pooled and the change scores were compared to CON using independent samples t-tests. Data are presented as mean ± sd. Statistical significance was p ≤ 0.05. Results: Mean age was 64 ± 8 years and Body Mass Index was 36.5 ± 6.9 kg·m^-2. Three control participants did not attend follow-up. For the INT groups (n = 27), 16 attended 75-100% of the weeks, 4 attended 50-67%, 4 never attended, and 3 dropped out due to unrelated illness/injury. Additionally, 13 participants regularly attended twice per week with 85% attendance. Participants reported walking 117 ± 77 minutes per week at home. There were no reported differences in PA (Yale Physical Activity Survey). However, waist circumference (-5.1 cm vs: 2.6 cm, p < 0.001), 6-min walk test (22m vs. 0.3m, p = 0.007) and quality of life (FACT-En: 7.9 vs. -0.5, p = 0.048) all improved significantly following the intervention compared to the control. Conclusions: About 25% of potential participants entered into the study, demonstrating the challenges of working with this population. However, once enrolled, the drop out rate was modest and adherence was high, demonstrating the acceptability and feasibility of this PA intervention in a diverse urban population of EC survivors. Furthermore, the results show promising effects that will need to be confirmed in a larger randomized control trial.