BACKGROUND Orthotopic liver transplantation (OLT) currently represents the treatment of choice for early hepatocellular carcinoma (HCC). Preoperatively known HCC (pkHCC) is diagnosed via imaging methods before OLT or before HCC is found postoperatively in the liver explant, denoted as incidental HCC (iHCC). The aim of this study was a comprehensive analysis of the post-transplantation survival of patients with iHCC and the identification of risk factors of iHCC occurrence in cirrhotic liver. METHODS We retrospectively reviewed 33 adult cirrhotic patients with incidentally found HCC, comparing them with 606 tumor-free adult cirrhotic patients with end-stage liver disease (group Ci) who underwent OLT in our center from January 1995 to August 2012. Within the same period, a total of 84 patients underwent transplantation for pkHCC. We compared post-transplantation survivals of iHCC, Ci, and pkHCC patients. In the group of cirrhotic patients (Ci + iHCC), we searched for risk factors of iHCC occurrence. RESULTS There was no difference in sex, Model for End-Stage Liver Disease score, and time spent on the waiting list in either group. In the multivariate analysis we identified age >57 years (odds ratio [OR], 3.37; 95% confidence interval [CI], 1.75-8.14; P < .001), hepatitis C virus or alcoholic liver disease (OR, 3.89; 95% CI, 1.42-10.7; P < .001), and alpha-fetoprotein level >6.4 μg/L (OR, 6.65; 95% CI, 2.82-15.7; P = .002) to be independent predictors of iHCC occurrence. Both the 1-, 3-, and 5-year overall survival (OS) and the 1-, 3- and 5-year recurrence-free survival (RFS) differed in iHCC patients compared with the Ci group (iHCC: OS 79%, 72%, and 68%, respectively; RFS 79%, 72%, and 63%, respectively; vs Ci: OS = RFS: 93%, 94%, and 87%, respectively; P < .001). CONCLUSIONS The survival of iHCC patients is worse than in tumor-free cirrhotic patients, but similar to pkHCC patients. The independent risk factors for iHCC occurrence in cirrhotic liver are age, hepatitis C virus, or alcoholic liver disease etiology of liver cirrhosis and alpha-fetoprotein level.