Although histological hepatitis occurs in the majority of hepatitis C virus (HCV)-infected liver transplant recipients, the natural history is highly variable. Whereas progression to cirrhosis occurs in up to 30% after 3 to 7 years, the disease remains stable in another third of patients, in whom protocol liver biopsies might be avoided. However, there is recent concern that with prolonged follow-up, some patients with initial benign recurrence may develop a late-onset aggressive course. Aims of the study are to determine the incidence and factors associated with this event. Based on yearly protocol biopsies (median, five biopsies; range, three to seven biopsies), we evaluated the histological outcome of 57 HCV type 1b-infected transplant recipients with initial benign recurrence, defined as stable histological state (fibrosis stage F0 or F1) during the first 3 years posttransplantation. Severe late-onset liver damage is defined as progression to F3 or F4 in patients with previous benign recurrence. Potential predictors of this event include demographics, donor-related factors, liver enzyme levels at 1 and 3 (or baseline) years posttransplantation, activity grade and fibrosis stage at 1 and 3 years posttransplantation, nonalcoholic steatohepatitis-related variables occurring within the first 3 years posttransplantation (diabetes, hyperlipidemia, obesity), use of some drugs (renin-angiotensin inhibitors, ursodeoxycholic acid), and the advent of any unusual event. The incidence of severe late-onset liver damage was 35% (n = 20). Twelve transplant recipients progressed to F3, whereas 8 transplant recipients progressed to F4. Sudden histological deterioration was observed on postoperative biopsy 5 in 12 patients; biopsy 6 or 7, in 7 patients; and biopsy 4, in 1 patient. Variables associated with this event in univariate analysis were fibrosis stage and activity grade (and its components) at baseline (P <.0001), recipient female gender (P =.04), alanine aminotransferase (ALT) level at 1 year posttransplantation (P =.02), and aspartate aminotransferase (AST) and ALT levels at baseline (P =.008 and P =.005, respectively). By multivariate analysis, only one variable was retained in the model: fibrosis stage at baseline (relative risk, 11; 95% confidence interval, 3 to 41; P =.0007), whereas AST level almost reached statistical significance (P =.07). In conclusion, delayed HCV-related severe liver damage is not infrequent in transplant recipients with initial benign recurrence, occurring in approximately one third of them. The presence of some degree of fibrosis at baseline appears to predict this sudden change in the natural history of recurrent hepatitis C. Based on these findings, we recommend continuing protocol biopsies and evaluating potential antiviral therapy in transplant recipients with evidence of some fibrosis (even if it is only portal).