The study found bone exchange disorder manifested by accelerated bone resorption, retarded bone formation, and the loss of the bone mineral density (BMD) of the axial and peripheral skeleton in 19 men (39 observations) 66 +/- 44 months following orthotopic heart transplantation (OTHT) and in 92 men 45 +/- 28 months after cadaveric kidney transplantation. An accelerated bone resorption, more pronounced in cadaveric kidney (CK) recipients, is associated with hyperparathyroidism (HPT) and renal dysfunction, while bone formation retardation is associated with a decrease in insulin-like growth factor-1 level. An increase in osteoprotegerin level is of compensatory character. The prominence of HPT depends on the degree of renal dysfunction; in CK recipients it also depends on the degree of the reduction in the levels of biologically active testosterone and estradiol. Reduction in BMD of the peripheral skeleton after OTHT are associated with the degree of renal dysfunction and a decrease in free testosterone index; after CK transplantation it is associated with HPT, the cumulative dose of glucocorticoids, reduction in the levels of biologically active testosterone and estradiol, as well as sex-hormone binding globulin (SHBG); reduction in spine BMD is only associated with SHBG.