1. INTRODUCTION. The latest statistics how that Japanese hemophilia patients infected with HIV-through clotting factor concentrates may survive more than 10 years after HIV-infection without showing an onset of AIDS [1]. Unfortunately, however, results of the recent surveillance have revealed that about half of hemophilia patients had also been infected with the hepatitis C virus (HCV) [2]. Therefore, some hemophilia patients might suffer from hepatocellular carcinoma triggered by HCV after some latent periods. In the present study, we computed the life time expectancy of hemophilia patients with two risks of HIV-and HCV infections. 2. METHOD. We used the Weibull hazard function h(t) for the hazard rate from AIDS after infection with HIV-1. In order to describe the hazard rate arising from hepatocellular carcinoma after HCV infection, we utilized the theoretical function c(t) with two parameters that were obtained previously by ourselves from a case-controlled study on hepatocellular carcinoma patients infected with HCV through blood transfusion [3]. Substituting necessary parameters estimated for Japanese hemophilia patients into h(t), the life time expectancy t was computed by the following integration; tau=integral of exp(-integral of h(t')+c(t¿) dt') dt, where t' means the time after HIV-infection, and t¿ is a variable composed of tU and times of HIV-and HCV infections. 3. RESULTS AND DISCUSSION. Without hepatocellular carcinoma, the life time expectancy tau of the patients infected with HIV-1 at the age of 20 was computed as 15.0 years. On the other hand, for the same patients with the risk of hepatocellular carcinoma through HCV infection at the age of 10, 15, 20 and 25 years old, values of tau were computed at 12.2, 13.3, 14.1 and 14.4 years, respectively. Especially noticeable was the reduction of tau in cases of HCV infection was prior to HIV-infection. In the present computation, the two risks from HIV-1 and HCV infections were assumed to be additive because no explicit interaction between them has been reported yet. Various long term effects have been found with the development of HIV/HCV therapies; that should also take into account the survival estimation and therapy planning for HIV-1 infected patients in the coming years.