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Patients with advanced liver disease are at increased risk for the development of hepatic osteodystrophy in the form of either osteomalacia or osteoporosis. The pathogenesis of these two bone diseases is multifactorial and includes, among other factors, alterations in vitamin D metabolism, malnutrition and hypogonadism. Little is known regarding vitamin D metabolism and the osteoblastic activity in liver transplant recipients. In order to clarify these issues, vitamin D metabolites and osteocalcin levels were measured prior to and 30 days following liver transplantation in 30 cirrhotic patients of various etiologies. While the mean plasma concentrations of 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D of the entire group of 30 patients were significantly greater prior to orthotopic liver transplantation (OLTx) as compared to those after OLTx (11.5 ± 8.6 vs. 7.4 ± 5.8 ng/ml, p = 0.0066 and 41.0 ± 34.6 vs. 20.4 ± 11.0 pg/ml, p = 0.0003, respectively), no significant changes in osteocalcin concentrations pre- or post-transplantation could be demonstrated (5.2 ± 3.0 vs. 6.4 ± 4.1 ng/ml, p = 0.51). Furthermore, no correlation between the plasma concentration of osteocalcin and either vitamin D metabolite, the prothrombin time or cyclosporine levels was found. The reasons for the normal levels of osteocalcin prior to OLTx can be explained by the fact that in vitamin-K-deficient states osteocalcin is predominantly decarboxylated and, therefore, a smaller proportion is bound to bone and/or the synthesis of osteocalcin is partially modulated by 1,25-dihydroxyvitamin D, the level of which has been found to be normal. The effect of cyclosporine on bone formation could explain the normal levels of osteocalcin in the post-OLTx period despite the suppressive effect of corticosteroids. The reduction in vitamin D levels seen following OLTx was probably a result of the corticosteroid therapy used postoperatively. Based upon these data, it can be concluded that osteocalcin levels in liver transplant recipients treated with a combination of cyclosporine/prednisone are usually within normal limits, probably as a result of the opposite pharmacologic effects of each drug on bone remodeling. As a result, osteocalcin levels may not be a reliable marker of bone formation in liver transplant recipients, at least in the early postoperative period.