GnRH agonists decrease bone mineral density and increase fracture risk in men with prostate cancer. Raloxifene increases bone mineral density in postmenopausal women, but its efficacy in hypogonadal men is not known. In a 12-month open-label study, men with nonmetastatic prostate cancer (n = 48) who were receiving a GnRH agonist were assigned randomly to raloxifene (60 mg/d) or no raloxifene. Bone mineral densities of the posteroanterior lumbar spine and proximal femur were measured by dual energy x-ray absorptiometry. Mean (+/-se) bone mineral density of the posteroanterior lumbar spine increased by 1.0 +/- 0.9% in men treated with raloxifene and decreased by 1.0 +/- 0.6% in men who did not receive raloxifene (P = 0.07). Bone mineral density of the total hip increased by 1.1 +/- 0.4% in men treated with raloxifene and decreased by 2.6 +/- 0.7% in men who did not receive raloxifene (P < 0.001). Similar between-group differences were observed in the femoral neck (P = 0.06) and trochanter (P < 0.001). In men receiving a GnRH agonist, raloxifene significantly increases bone mineral density of the hip and tends to increase bone mineral density of the spine.