Although hyperinsulinemia and its associated metabolic syndrome (MS) have been implicated in the progression of hepatic fibrosis in hepatitis C virus (HCV) patients, little is known about the consequences of MS after orthotopic liver transplantation (OLT). The aim of this study was to assess the association between MS and fibrosis progression in patients with recurrent HCV after OLT. We identified all OLT/HCV patients (1998-2005) with at least 2 post-OLT liver biopsies. MS was defined with Adult Treatment Panel III criteria at 1 year post-OLT. The Ludwig-Batts scoring system was used to stage all biopsies (408 biopsies from 95 patients). The first biopsy that showed progression post-OLT was used for the time-to-progression analysis. Univariable and multivariable logistic regression analysis was performed to identify factors associated with fibrosis progression. MS was present in 50% of patients. Average follow-up to last available biopsy was 24 ± 17 months, during which 72% of subjects had fibrosis progression. The overall median rate of fibrosis progression was 0.08 units per month (Q25, Q75: 0.0, 0.17). By univariable analysis, high HCV RNA at 4 months post-OLT (P < 0.001), diabetes (P = 0.046), cytomegalovirus infection (P = 0.006), and MS (P = 0.049) were associated with progression of fibrosis. In multivariable analysis, MS was independently associated with progression of fibrosis beyond 1 year after OLT (odds ratio = 6.3, P = 0.017). A high viral load at 4 months post-OLT (odds ratio = 1.1, P = 0.004) and steroid therapy for acute rejection (odds ratio = 1.9, P = 0.05) were independently associated with fibrosis progression. In conclusion, MS, a potentially modifiable disease, is common and is strongly associated with long-term fibrosis progression in the setting of recurrent HCV after OLT. Liver Transpl 14:1287–1293, 2008. © 2008 AASLD.