BACKGROUND: There are limited data on the physical effects of androgen deprivation therapy (ADT) for prostate cancer (PC), and on the relationships of such measures of adiposity and strength to cardiovascular outcomes. OBJECTIVES: The primary objective of this study was to evaluate the relationships of measures of adiposity and strength to cardiovascular outcomes (cardiovascular death, myocardial infarction, stroke, heart failure, arterial revascularization, peripheral arterial disease, and venous thromboembolism) in patients with PC. A secondary objective was to characterize the relationships between ADT use and 12-month changes in these physical measures. METHODS: This international, prospective cohort study included 3,967 patients with PC diagnosed in the prior 12 months or being treated with ADT for the first time. Median follow-up duration was 2.3 years. RESULTS: Participants' mean age was 68.5 years, and 1,731 (43.6%) were exposed to ADT. ADT was associated with a 1.6% increase in weight, a 2.2% increase in waist circumference, a 1.6% increase in hip circumference, a 0.1% increase in waist-to-hip ratio, a 27.4% reduction in handgrip strength, and a 0.1% decrease in gait speed. High waist circumference and low handgrip strength were associated with adverse cardiovascular outcomes. Adjusting for age, education, race, tobacco and alcohol use, physical activity, cardiovascular disease, glomerular filtration rate, and ADT use, waist circumference above the highest quartile (110 cm) and handgrip strength below the lowest quartile (29.5 kg) were associated with higher likelihoods of a future cardiovascular event, with respective HRs of 1.40 (95% CI: 1.03-1.90;  = 0.029) and 1.59 (95% CI: 1.14-2.22;  = 0.006). CONCLUSIONS: ADT was associated with increased adiposity and reduced strength over 12-month follow-up. High waist circumference and low baseline strength were associated with future adverse cardiovascular outcomes.