The objective of this study was to gain an understanding about current attitudes towards sex in older adults in Japan, which has the oldest population in the world, and about the sex lives of older adults, and to clarify how these factors are related to life satisfaction in older adults. Questionnaires were distributed to 1979 persons, and 646 responses were received (for a response rate of 31.4%). In the respondents who were included in the analysis, who ranged in age from 65 to 97 years, more men than women responded that “Sex is communication,” “Sex is enjoyable,” and “A sex life is important.” In all age categories, men wanted a more straightforward sexual relationship than women, and women wanted a less straightforward sexual relationship than men. The level of life satisfaction was higher in married respondents who had a positive attitude towards sex, and in older adults who had an intimate relationship, with or without sexual intercourse. This study sheds light on the current state of sexuality in older adults in Japan and shows that a positive attitude towards sex, and an intimate relationship, are associated with higher levels of life satisfaction, whether or not there is sexual intercourse or a desire for it.