Objective: This study was designed to determine the effect of different varieties of maca (Lepidium meyenii) on bone structure in ovariectomized (OVX) rats. Materials and Methods: 36 female rats were randomly divided into 6 groups: sham and OVX rats treated with vehicle, estradiol (40 μg/kg), black, yellow or red maca (63 mg/ml) for 4 weeks. At the end of the treatment, uterine weight, femoral bone and lumbar vertebra histomorphology were assessed. Results: Ovariectomy reduced weight, diameter and width of the femoral bone. Estradiol, black and red maca treatment reduced the effect of ovariectomy on these variables. Histological analyses revealed that estradiol, black and red maca treatments reversed the effect of ovariectomy by increasing the trabecular bone area in the second lumbar vertebra. Uterine weight was reduced in OVX rats, and estradiol but neither black nor red maca increased uterine weight. Conclusion: Red and black maca have protective effects on bone architecture in OVX rats without showing estrogenic effects on uterine weight. © 2010 S. Karger AG.