BACKGROUND: Men diagnosed with prostate cancer have increased risk for disease progression, cardiovascular events, and impairments in quality of life. This pilot study evaluated the feasibility of a randomized walking group intervention to improve quality of life, circulating biomarkers, and morbidity among men with newly diagnosed prostate cancer. METHODS: Men were recruited at Örebro University Hospital, Sweden, and randomized to an 11-week walking group intervention (n = 21) or usual care (n = 20). The intervention included weekly 1-hour walking group sessions and maintenance of 10,000 steps/day. Outcomes were changes in body composition, clinical factors, biomarkers of cardiovascular health, and quality of life between baseline and end of study. Analysis of covariance was used to compare outcomes in each group adjusted for baseline values. RESULTS: All 41 men randomized completed the 11-week trial. Men assigned to the intervention walked on average 10,644 steps/day, and 92% reported missing 2 or fewer sessions. Both groups experienced similar weight loss at 11 weeks. Men in the intervention had a significant adjusted mean change in high-density lipoprotein of 0.14 mmol/L (95% confidence interval [CI], 0.01-0.27; P = .04), and suggestive adjusted mean changes in low-density lipoprotein of -0.22 mmol/L (95% CI, -0.47 to 0.03; P = .08) and in systolic blood pressure of -8.5 mm Hg (95% CI, -21.2 to 4.2; P = .18), compared with the usual care group. CONCLUSIONS: A walking group intervention among men with recent diagnosis of prostate cancer is feasible and potentially effective in improving cardiovascular health. A larger randomized trial of longer duration is required to elucidate its potential for improvement in longer term outcomes.