Few studies have examined the association between Japanese diet and mortality outcomes. We analysed the relationship between a healthy Japanese diet and all-cause and cause-specific mortality using the database from the National Integrated Project for Prospective Observation of Non-Communicable Diseases and its Trends in the Aged, 1980. At baseline in 1980, data were collected on study participants aged ≧30 years from randomly selected areas in Japan. We defined a measure of a healthy reduced-salt Japanese diet based on seven components from FFQ. The total score ranged from 0 to 7, with 0 being least healthy and 7 being most healthy. Participants were divided into approximate tertiles of dietary scores (0–2, 3 and 4–7 scores). After excluding participants with co-morbidities, we followed 9086 participants (44 % men) for 19 years. There were 1823 all-cause and 654 cardiovascular deaths during the follow-up. With the dietary score group 0–2 serving as a reference, the Cox multivariate-adjusted hazard ratios for groups with scores 3 and 4–7 were 0·92 (95 % CI 0·83, 1·04) and 0·78 (95 % CI 0·70, 0·88) for all-cause mortality (trend P < 0·0001), and 0·91 (95 % CI 0·75, 1·10) and 0·80 (95 % CI 0·66, 0·97) for cardiovascular mortality (trend P = 0·022). Adherence to a healthy reduced-salt Japanese diet was associated with an approximate 20 % lower rate of all-cause and cardiovascular mortality.