This study examined bone density among postmenopausal Buddhist nuns and female religious followers of Buddhism in southern Taiwan and related the measurements to subject characteristics including age, body mass, physical activity, nutrient intake, and vegetarian practice. A total of 258 postmenopausal Taiwanese vegetarian women participated in the study. Lumbar spine and femoral neck bone mineral density (BMD) were measured using dual-photon absorptimetry. BMD measurements were analyzed first as quantitative outcomes in multiple regression analyses and next as indicators of osteopenia status in logistic regression analyses. Among the independent variables examined, age inversely and body mass index positively correlated with both the spine and femoral neck BMD measurements. They were also significant predictors of the osteopenia status. Energy intake from protein was a significant correlate of lumbar spine BMD only. Other nutrients, including calcium and energy intake from nonprotein sources, did not correlate significantly with the two bone density parameters. Long-term practitioners of vegan vegetarian were found to be at a higher risk of exceeding lumbar spine fracture threshold (adjusted odds ratio = 2.48, 95% confidence interval = 1.03–5.96) and of being classified as having osteopenia of the femoral neck (3.94, 1.21–12.82). Identification of effective nutrition supplements may be necessary to improve BMD levels and to reduce the risk of osteoporosis among long-term female vegetarians.