Background Long-term prostate cancer (PCa) survivors are at increased risk for comorbidities and physical deconditioning. Objective To determine the effectiveness of a year-long randomised controlled trial of exercise training in PCa survivors >5 yr postdiagnosis on physical functioning. Design, setting, and participants Between 2010 and 2011, 100 long-term PCa survivors from Trans-Tasman Radiation Oncology Group 03.04 Randomised Androgen Deprivation and Radiotherapy previously treated with androgen-deprivation therapy and radiation therapy were randomly assigned to 6 mo of supervised exercise followed by 6 mo of a home-based maintenance programme (n = 50) or printed educational material about physical activity (n = 50) for 12 mo across 13 university-affiliated exercise clinics in Australia and New Zealand. Intervention Supervised resistance and aerobic exercise or printed educational material about physical activity. Outcome measurements and statistical analysis The primary end point was a 400-m walk as a measure of cardiovascular fitness. Secondary end points were physical function, patient-reported outcomes, muscle strength, body composition, and biomarkers. Analysis of covariance was used to compare outcomes for groups at 6 and 12 mo adjusted for baseline values. Results and limitations Participants undergoing supervised exercise showed improvement in cardiorespiratory fitness performance at 6 mo (-19 s [p = 0.029]) and 12 mo (-13 s [p = 0.028]) and better lower-body physical function across the 12-mo period (p <0.01). Supervised exercise also improved self-reported physical functioning at 6 (p =.006) and 12 mo (p = 0.002), appendicular skeletal muscle at 6 mo (p = 0.019), and objective measures of muscle strength at 6 and 12 mo (p <0.050). Limitations included the restricted number of participants undertaking body composition assessment, no blinding to group assignment for physical functioning measures, and inclusion of well-functioning individuals. Conclusions Supervised exercise training in long-term PCa survivors is more effective than physical activity educational material for increasing cardiorespiratory fitness, physical function, muscle strength, and self-reported physical functioning at 6 mo. Importantly, these benefits were maintained in the long term with a home-based programme with follow-up at 12 mo. Clinical trial registry The effect of an exercise intervention on cardiovascular and metabolic risk factors in prostate cancer patients from the RADAR study, ACTRN: ACTRN12609000729224. © 2013 European Association of Urology.