Androgen deprivation therapy (ADT) for prostate cancer (PCa) has multiple adverse effects on musculoskeletal health. This 12-month randomised controlled trial aimed to assess the effects of multi-component exercise training combined with whey protein, calcium and vitamin D supplementation on bone mineral density (BMD), structure and strength, body composition, muscle strength and physical function in ADT-treated men.Seventy ADT-treated men were randomised to exercise plus supplementation (Ex+Suppl; n=34) or usual care (Control; n=36). Ex+Suppl involved thrice weekly progressive resistance training plus weight-bearing impact exercise with daily multi-nutrient supplementation. Primary outcomes were DXA hip and spine areal BMD. Secondary outcomes included: tibia and radius pQCT volumetric BMD, bone structure and strength; DXA body composition; pQCT muscle and fat cross-sectional area and muscle density; muscle strength and physical function.Sixty men (86%) completed the study. Mean exercise and supplement adherence were 56% and 77%, respectively. There were no effects of the intervention on bone or body composition outcomes. Ex+Suppl improved leg muscle strength (net difference [95% CI] 14.5% [-0.2, 29.2], P=0.007) and dynamic mobility (four-square-step test time, -9.3% [-17.3, -1.3], P=0.014) relative to controls. Per-protocol analysis of adherent participants (≥66% exercise, ≥80% supplement) showed Ex+Suppl preserved femoral neck aBMD (1.9% [0.1, 3.8], P=0.026) and improved total body lean mass (1.0 kg [-0.23, 2.22], P=0.044) relative to controls.Exercise training combined with multi-nutrient supplementation had limited effect on ameliorating the adverse musculoskeletal consequences of ADT, likely related to the modest intervention adherence.