Liver transplantation (OLT) is often complicated by renal failure. Hepatitis C (HCV) is said to be a risk factor for renal failure after OLT, but few studies have analyzed this directly. We evaluated all patients who received a liver transplant from 1995 through 2003. There were 147 patients infected with HCV and 202 not infected. Patients with HCV were further divided into 114 patients with benign HCV and 33 patients with severe HCV defined by bridging fibrosis or cirrhosis. The groups were evaluated for the development of renal insufficiency defined as a creatinine above 1.8 mg/dL on three consecutive occasions or renal failure as defined by the need for dialysis or renal transplant. The incidence of renal failure in patients with HCV was 10.2% and in patients without HCV was 3.5% (P = .004). Patients with severe HCV had an incidence of 12.1% vs 9.7% for patients with mild HCV. The linear trend in renal failure from non-HCV to mild HCV to severe HCV was significant (P = .012). The incidence of renal insufficiency was 23.4% in patients with HCV and 14.9% in patients without HCV (P = .080). The incidence was 32.3% in patients with severe HCV and 20.6% in patients with mild HCV. The trend in renal insufficiency across the three groups was mildly significant (P = .042). On multivariate analysis, HCV was a risk factor for renal failure with a relative risk of 2.58 (P = .045). The study suggests that HCV and the severity of recurrent HCV are risk factors for renal dysfunction after liver transplantation.