Fractures occur in 11 to 26% of renal allograft recipients after transplantation despite improvements in bone and mineral disorders. This high fracture rate is likely a consequence of accelerated osteopenia. The cause of posttransplant bone loss is multifactorial, and patients with insulin-dependent diabetes mellitus and renal failure may have additional fracture risks such as low turnover bone disease. This retrospective cohort study was undertaken to determine the long-term incidence and the potential risk factors of posttransplant fractures in patients with insulin-dependent diabetes mellitus undergoing combined kidney-pancreas allograft transplantation. Thirty-five patients with insulin-dependent diabetes mellitus who received a combined kidney-pancreas allograft between 1987 and 1992 were evaluated. Thirty-five kidney allograft recipients matched for age, gender, and the date of transplant were also reviewed. The fracture incidence in the kidney-pancreas group was 49% after transplantation. The rate of first fracture after kidney-pancreas transplantation was 12.1% per patient year, resulting in a 5-yr fracture-free rate of 48%. The initial fracture occurred at a mean of 31.06 +/- 19.9 mo. Steroid exposure was found to increase the risk of fracture, and analysis by means of a Cox regression model estimated that an increase in cumulative steroid exposure of 10 mg/kg at any given month increased the hazard of sustaining a fracture by 9% (95% confidence interval for hazard ratio, 1.01 to 1.18; P = 0.031). This analysis suggests that kidney-pancreas recipients are at significant risk of sustaining a fracture within a few years after transplantation.