Abstract The main objective of this study was to estimate the cumulative mortality risk for lung cancer according to smoking status and exposure to secondhand smoke (SHS) in Japan. We applied a life-table method to estimate the cumulative risk. Estimated lifetime cumulative risk for 20-year-old non-smokers, former, and current smokers was 3.2%, 7.6%, and 14.9% for men and 1.9%, 5.6%, and 7.2% for women, respectively. For males, the estimated risk was 3.2% for non-smokers not exposed to SHS and 4.1% for non-smokers exposed to SHS. For females, the estimated risk was 1.9% for non-smokers not exposed to SHS and 2.4% for non-smokers exposed to SHS. Lifetime cumulative mortality risk differed greatly according to smoking status. Moreover, SHS exposure resulted in observable differences in lifetime mortality risk. This study may be useful for the development of tailored prevention programs.