Purpose. Despite advanced medical treatment options, many prostate cancer patients are still confronted with unfavorable physical and psychological burdens. Physical exercise has proven to be beneficial for prostate cancer patients, yet specific exercise offers are rare. The ProRehab Study aimed to evaluate the exercise program offered in rehabilitative prostate cancer sports groups in Germany and determine whether it is beneficial for patients following prostatectomy. Methods. Eighty-five prostate cancer patients were recruited for a multicenter, 2-armed, nonrandomized controlled trial 6 to 12 weeks after prostatectomy. The intervention group (n = 56) took part in a 15-month supervised multimodal exercise program. Exercise sessions took place once a week for 60 minutes at a moderate intensity (3.84-4.84 MET-hour). The control group (n = 29) received no intervention. Outcomes included aerobic fitness, activity levels, quality of life, disease-and treatment-related adverse effects, such as urinary incontinence and erectile dysfunction, and relapse-relevant blood values. Intention-to-treat analysis was performed. Results. A significant between-group difference was observed in the urinary symptom score (P = .027). Physical fitness, urinary incontinence, physical, role, emotional, and social functioning, as well as further disease-and treatmentrelated side effects (dyspnea, urinary, and bowel symptoms) significantly improved within the intervention group. Erectile dysfunction and physical activity levels improved similarly in both groups. Conclusions. The presented data hint at the potential of rehabilitative sports groups for prostate cancer patients. However, according to the current state of the art, exercise intensity and volume may need to be increased to enhance the effects. A number of shorter studies (8-24 weeks) have proven significant between-group differences in quality of life, incontinence, and fitness outcomes when patients exercised 2 to 3 times per week. This is the first exercise intervention study with prostate cancer patients that was conducted over 15 months. Further studies are necessary to investigate whether prostate cancer patients recover sooner when receiving a supervised exercise program.