Purpose: To investigate the effects of a supported home-based progressive resistance exercise training (RET) programme on indices of cardiovascular health, muscular strength and health-related quality of life (HR-QoL) in prostate cancer (PCa) patients after treatment with robot-assisted radical prostatectomy (RARP). Methods: This study was a single-site, two-arm randomised controlled trial, with 40 participants randomised to either the intervention or control group over a 10-month period. In addition to receiving usual care, the intervention group completed three weekly RET sessions using resistance bands for 6 months. Participants performed 3 sets of 12–15 repetitions for each exercise, targeting each major muscle group. The control group received usual care only. Brachial artery flow-mediated dilatation (FMD) was the primary outcome and assessed at baseline, 3 and 6 months. Secondary outcomes included body weight, body fat, aerobic fitness, strength and blood-borne biomarkers associated with cardiometabolic risk. Results: There was no significant difference between the groups in FMD at 3 or 6 months. However, there were improvements in aerobic exercise capacity (P < 0.01) and upper- (P < 0.01) and lower-limb (P = 0.01) strength in favour of the RET group at 6 months, accompanied by greater weight loss (P = 0.04) and a reduction in body fat (P = 0.02). Improvements in HRQoL were evident in the RET group at 3 and 6 months via the PCa-specific component of the FACT-P questionnaire (both P < 0.01). Five adverse events and one serious adverse event were reported throughout the trial duration. Conclusion: This study demonstrates that home-based RET is an effective and safe mode of exercise that elicits beneficial effects on aerobic exercise capacity, muscular strength and HR-QoL in men who have undergone RARP. Trial registration: ISRCTN10490647.