We assessed the clinical and biochemical parameters associated with the development of posttransplantation diabetes (PTDM) in 52 liver transplant recipients followed up for 1 year. Diabetes was present before transplantation in 9.6% (5 of 52) of patients, and PTDM occurred in 23% (11 of 47) of the remaining liver transplant recipients. Of the 13 patients who had hepatitis C as the cause of their liver failure (HC-LD), 8 (62%) developed PTDM; of the 34 patients with other causes of liver failure, 3 (9%) developed PTDM (p < 0.001). Posttransplantation diabetes was also associated with the development of early posttransplantation hyperglycemia, a higher number of liver rejection episodes, and lower serum albumin levels at 6 months. The association of PTDM with HC-LD remained significant in a logistic regression model after adjustment for potential confounding variables.We conclude that PTDM is common in liver transplant recipients. Associated clinical parameters predictive of PTDM include a diagnosis of HC-LD before transplantation, the development of early hyperglycemia after transplantation, multiple episodes of posttransplantation liver rejection and low serum albumin levels at 6 months. The fact that HC-LD remained an independent risk factor for the development of PTDM may suggest a direct or immune-mediated pancreatic effect of the virus.