The aim of this study was to clinically characterize young patients with hepatitis‐C‐related cirrhosis. We compared 27 patients with liver cirrhosis (Group LC) who were anti‐HCV positive, aged 40 years or less at the time of diagnosis, with 323 consecutive patients with HCV‐related chronic hepatitis (Group CH) matched for age and gender. Furthermore, Group LC was divided into two arbitrary groups (29–35 years, n = 8 /36–40 years, n = 19), based on the age of patients at the time of diagnosis of liver cirrhosis. Patients' characteristics and family history were investigated, and the frequency of transporter associated with antigen processing 2 (TAP2) was determined. A family history of liver disease was present in 40.7% of Group LC but in 18.0% of Group CH (P < 0.05). The younger the age of diagnosis of cirrhosis in Group LC, the higher the frequency of a positive family history (29–35 years, 87.5%; 36–40 years, 21.1%, P < 0.05). The frequency of TAP2*0201 was significantly higher in young adult patients with HCV‐related liver cirrhosis than in HCV carriers with normal ALT (P < 0.05), and tended to be higher than in uninfected normal subjects (P = 0.05). The cumulative survival rate of cirrhosis patients with family history of liver diseases was significantly lower than that of cirrhosis patients without such history (P < 0.05). Our findings suggest that a positive family history of liver disease and TAP2*0201 polymorphism may be risk factors for HCV‐related liver cirrhosis in young adults. J. Med. Virol. 64:109–116, 2001. © 2001 Wiley‐Liss, Inc.