In an effort to determine the influence of immunosuppressive therapy and other clinical variables on posttransplant osteopenia, vertebral bone density was measured at least 6 months after transplantation in 65 adult primary renal transplant recipients receiving a variety of immunosuppressive regimens. Fifteen of the 65 patients (23%) had vertebral bone densities below a fracture threshold of 1.0 g hydroxyapatite/cm2. Multivariate analyses indicated that cumulative steroid dose and female gender were the major independent predictors of low vertebral bone density. In women, postmenopausal status also was associated with osteopenia. There was no correlation between cumulative cyclosporine dose and bone density. Results of this study indicate that posttransplant osteopenia is common in renal transplant recipients, including those treated with CsA. Although CsA has allowed the use of lower cumulative doses of steroids, concomitant steroid therapy remains the preeminent factor accounting for loss of bone density.