Aim The present study examined sex and age differences in taste sensitivity among young adult, young‐old and old‐old Japanese. Methods Participants were divided into three groups comprising 477 men and 519 women in the young‐old group (aged 69–71 years), 449 men and 500 women in the old‐old group (aged 79–81 years), and 35 men and 35 women in the young adult group (aged 24–32 years). Recognition thresholds for the four basic tastes were measured using the 1‐mL whole mouth gustatory test, in which taste solutions of the four basic tastes were tested in five concentrations. Results Young adults showed significantly lower recognition thresholds than the young‐old group, and the young‐old group showed significantly lower recognition thresholds than the old‐old group. Among the young‐old and old‐old groups, women showed significantly lower recognition thresholds than males for sour, salty and bitter tastes, but there was no sex difference in the sweet taste threshold between the two groups. Conclusions The present study confirmed that there are age and sex differences in taste sensitivity for the four basic tastes among young adult, young‐old, and old‐old Japanese, and that the sensitivity of sweet taste is more robust than the other tastes. Geriatr Gerontol Int 2016; 16: 1281–1288.