BACKGROUND/AIMS: Nonalcoholic fatty liver disease (NAFLD) has been characterized by a wide spectrum of liver damages that span from steatosis to cryptogenic liver cirrhosis and even to hepatocellular carcinoma (HCC). The aims of this study were to determine whether the prevalence of HCC arising from cryptogenic cirrhosis has increased during the last ten years and to characterize the clinical features of cryptogenic HCC in Korea. METHODS: A retrospective and hospital-based analysis of the clinical data was done in 1,145 HCC patients; group A (Jan. 1993-Dec. 1995), group B (Jan. 2000-Dec. 2002). The etiologies of HCC with liver cirrhosis in group A and group B were analyzed. The risk factors of NAFLD such as obesity, type 2 diabetes mellitus, hypertriglyceridemia and hypertension between cryptogenic HCC and HCC with well-defined etiologies were compared. RESULTS: The major leading causes of HCC in each group were hepatitis B virus infection, followed by alcohol, hepatitis C virus and cryptogenic. There was a significant increase in the proportion of cryptogenic HCC in group B (A: 2.3%, B: 5.4%, p<0.05). In the case of HCV, it was 5.3% in group A and 9.9% in group B (p<0.05). Although the prevalence of cyptogenic HCC was significantly increased at an interval of seven years apart, there was no significant difference in the proportions of risk factors of NAFLD between cryptogenic HCC group and well-defined etiology group. CONCLUSIONS: The prevalence of cryptogenic HCC was significantly increased in Korea during the last decade. Although statistically insignifcant, there was a trend toward the higher proportion of risk factors with NAFLD in patients with cryptogenic HCC. This suggests that increased proportion of risk factors associated for NAFLD may have contributed to the development of cryptogenic HCC.