OBJECTIVE: To investigate the response of trabecular bone of ovariectomized (OVX) rats to nylestriol. METHODS: Thirty-three female Wistar rats were randomly divided into three groups, 11 rats in each: nylestriol-treated group (E), OVX and the control (C). The OVX rats were used as a model for osteoporosis. After being fed with nylestriol for 3 months, all rats were sacrificed. The effect of nylestriol on bone microarchitecture and dynamics were studied by bone histomorphometry. RESULTS: The data suggest that trabecular bone volume, mean trabecular width, density and cortical thickness were remarkably reduced in OVX group (P < 0.05) while tetracycline labeled surface, osteoid surface and bone turnover rate were increased in comparison with that in C group (P < 0.05). The bone turnover rate and trabecular bone volume were improved with the treatment of nylestriol for 3 months in the OVX rats(P < 0.05). CONCLUSIONS: Trabecular bone volume and bone turnover rate can be improved by 3 month administrations of nylestriol in osteoporotic rat models.