Dental caries studies on ancient skeletal remains and those which focus on sex differences and changes with aging are almost unknown worldwide. This study was aimed to clarify age- and sex-related changes in caries prevalence in Jomon people in Japan and to reveal more information on their livelihood and surrounding environment. The materials were human skeletal remains of a total of 271 individuals from the Jomon period. Determination of sex and age estimation were performed using these materials. They were divided into 4 groups : male and female young/early middle-age groups, and male and female late middle-age/elderly groups. As a result : (1) in males, there was almost no difference in the dental caries rate between the young/early middle-age group and late middle-age/elderly group ; (2) in females, the dental caries rate was significantly higher in the late middle-age/elderly group compared to the young/early middle-age group ; (3) in both males and females, the dental caries rate significantly increased with aging in the maxillary teeth compared to the mandibular teeth ; and (4) overall, females had higher dental caries rates than males in the young/early middle-age group and late middle-age/elderly group. From the aforementioned results, females tended to have higher dental caries rates than males in the Jomon period. A difference in the dietary habits of males and females is thought to be the cause of such a difference. In particular, a substantial increase in the dental caries rate in late middle-aged and elderly females leads one to speculate that females of that time period preferred sweet foods.