OBJECTIVE To compare the effects of raloxifene and placebo on body composition and muscle strength. DESIGN Randomized, double-blind, placebo-controlled trial involving 198 healthy women aged 70 years or older conducted between July 2003 and January 2008 at the University Medical Centre, Utrecht, The Netherlands. METHODS Participants were randomly assigned to receive raloxifene 60 mg or placebo daily for 12 months. Measurements were taken at baseline, 3, 6, and 12 months, and change from baseline was calculated. Main outcome measures were body composition (bioelectrical impedance analysis), muscle strength, and muscle power (maximum voluntary isometric knee extension strength, explosive leg extensor power, and handgrip strength). RESULTS At 12 months, the body composition of women taking raloxifene was significantly different from that of women taking placebo: fat-free mass (FFM) had increased by a mean of 0.83 (2.4) kg in the raloxifene group versus 0.03 (1.5) kg in the placebo group (P=0.05), and total body water had increased by a mean of 0.6 (1.8) litres in the raloxifene group versus a decrease of 0.06 (1.1) litres in the placebo group (P=0.02). Muscle strength and power were not significantly different. CONCLUSION Raloxifene significantly changed body composition (increased FFM; increased water content) compared with placebo in postmenopausal women.