Background.Chronic viral hepatitis averages 15% to 20% in heart transplant patients. Several studies have shown that ursodiol may improve liver biochemistry in patients with chronic hepatitis. We used a double-blind randomized controlled trial to evaluate the effect of ursodiol in heart transplant patients with chronic viral hepatitis.Methods.Thirty heart patients with chronic viral hepatitis B, C, or non-A-G received ursodiol, 800 mg per day (group 1), and 30 received placebo (group 2) for 12 months. Endpoints were improvement in liver biochemical tests and in total Knodell score. Intent-to-treat and per-protocol analyses were performed.Results.At entry, both groups were comparable for all of the studied parameters. During the study period, serum alanine aminotransferase, aspartate aminotransferase, and &ggr;-glutamyl transpeptidase variations were not different between group 1 and group 2 patients. Knodell score improved in 20% of group 1 patients and in 43% of group 2 patients (NS). Adverse events or mortality were not different in the two groups during the study period. Similar results were observed by intent-to-treat and per-protocol analyses.Conclusions.A 12-month course of ursodiol therapy had no effect on liver enzymes or liver histology in heart transplant patients with chronic hepatitis.