In 1980, cancer was the most common cause of death in Japan accounting for 23.9% of all deaths. Although stomach cancer is still the major type of malignant neoplasm, trends indicate that, in the future, lung cancer will take this position. The information on lung cancer obtained from Japanese vital statistics was analysed to show secular trends as well as comparisons between the sexes. The information also examined the difference between rural and urban areas and clarified some of the causal factors in the increase of lung cancer, especially among men. Factual increase in lung cancer among males compared with females may be considered to be mainly related to excessive smoking habits.
