Hypogonadism and oxidative stress increase the risk for developing osteoporosis. The objective of this researchwas to evaluate the efficacy of drinking grapefruit juice on bone quality in orchidectomized (ORX) and non-ORX rats. Fifty-six 90-day-old male Sprague-Dawley rats were equally divided into four groupsnon-ORX rats (sham), sham. grapefruitjuice, ORX, and ORX. grapefruit juiceand treated for 60 days. Thereafter, all rats were sacrificed to determine the plasmaantioxidant status, insulin-like growth factor I (IGF-I), and indices of bone turnover, bone quality, and calcium and magne-sium concentrations in the bone, urine, and feces. Orchidectomy decreased (P. .05) antioxidant status, bone quality, andbone mineral contents and increased (P. .05) indices of bone turnover, urinary deoxypridinoline, calcium, and magnesium,and fecal calcium excretions. In contrast to the ORX group, ORX rats that drank grapefruit juice had an increase (P. .05)in antioxidant status, bone density, and bone mineral contents, delayed femoral fracture, and slowed down (P. .05) boneturnover rate and tended to have a decrease (P. .08) in urinary deoxypridinoline. In sham-treated animals, drinking grape-fruit juice increased (P. .05) bone density and tended to increase the femoral strength. The concentration of IGF-I in theplasma was not affected across treatments. In conclusion, drinking grapefruit juice positively affected bone quality by en-hancing bone mineral deposition in ORX rats and by improving bone density in non-ORX rats via an undefined mechanism.