BACKGROUND AND AIM: The current prevalence of hepatitis C virus infection and hepatitis C virus-associated mortality in Japan falls short of the World Health Organization goal of viral hepatitis elimination by 2030. We aimed to evaluate the trends in hepatitis C virus-associated mortality in Japan. METHODS: This nationwide observational study used the Japanese Vital Statistics from 1998 to 2017 and included all Japanese hepatitis C virus-associated deaths (84 936) of adults aged ≥ 40 years. We calculated the crude and age-standardized mortality rates per 100 000 persons by age and sex. Joinpoint regression analysis was used to identify significant changing points in trends and to estimate the annual percentage changes and the average annual percentage changes for the entire study period. RESULTS: The crude mortality rate per 100 000 persons (annual death number) increased from 5.5 (3548) in 1998 to 7.0 (4843) in 2005 and decreased to 4.0 (3095) in 2017. By 2017, the crude mortality rates per 100 000 persons among men and women had dropped to 3.6 and 4.3, respectively. The age-standardized mortality rate was higher in women than in men. The average annual percentage change was -3.8% (95% confidence interval: -5.0 to -2.5). The declining trend was more rapid in men (-4.5%, 95% confidence interval: -5.3 to -3.6) than in women (-2.7%, 95% confidence interval: -3.8 to -1.6). CONCLUSIONS: Trends in hepatitis C virus-associated mortality rates have declined in an accelerating manner in Japan, especially among men.