Each year, more than 600,000 adults are diagnosed with an obesity-associated cancer. Maintenance of a healthy body weight may reduce the likelihood of developing these cancers, slow the deterioration of health, and lower the risk of recurrence. Exercise is a commonly prescribed method of weight management in cancer survivors, but data are limited regarding the individualized benefits experienced by obese versus non-obese patients. PURPOSE: To compare the effects of exercise on obese and non-obese cancer survivors. METHODS: We enrolled 157 patients in a 10-week exercise program. At baseline, we determined anthropometric and cardiovascular profiles, psychological wellbeing, and physical functioning. Follow-up data were collected on subjects who completed the program (n=58). Obesity was defined by a body mass index ≥ 30 kg/m2. Cardiovascular variables were blood pressure and heart rate. Wellbeing was assessed with questionnaires evaluating fatigue, insomnia, and depression. Physical function was measured with 13 tests of strength, coordination, aerobic capacity, and flexibility. Independent-samples t tests compared baseline characteristics and changes in outcome measurements of obese and non-obese patients. RESULTS: At baseline, obese (40%) and non-obese (60%) patients were similar with the exception that obese patients performed poorer in the six-minute walk (p<0.001) and timed up-and-go (p=0.012) while they were stronger in push (p=0.017) and pull (p=0.040) assessments. Retention rate did not differ by obesity status (p=0.853). From baseline to follow-up, patients improved in wellbeing and most functional tests, but there were no differences in improvement between obese and non-obese patients in any component of their cardiovascular profile, psychological health, or physical functioning (p>0.190). CONCLUSION: Obese and non-obese cancer survivors have similar profiles at baseline and generally improve with exercise. Exercise may be more critical to obese patients, not due to cardiovascular, psychological, or functional changes, but because of the risk of recurrence associated with excess adiposity. Our findings reiterate the importance of exercise to the cancer survivor, regardless of body composition, but there is potential for bias owing to the high dropout rate found in our study.