OBJECTIVE: To study secular trends in self reported sexual behaviour among 70 year olds. DESIGN: Cross sectional survey. Settings Four samples representative of the general population in Gothenburg, Sweden. PARTICIPANTS: 1506 adults (946 women, 560 men) examined in 1971-2, 1976-7, 1992-3, and 2000-1. MAIN OUTCOME MEASURES: Sexual intercourse, attitudes to sexuality in later life, sexual dysfunctions, and marital satisfaction. RESULTS: From 1971 to 2000 the proportion of 70 year olds reporting sexual intercourse increased among all groups: married men from 52% to 68% (P=0.002), married women from 38% to 56% (P=0.001), unmarried men from 30% to 54% (P=0.016), and unmarried women from 0.8% to 12% (P<0.001). Men and women from later birth cohorts reported higher satisfaction with sexuality, fewer sexual dysfunctions, and more positive attitudes to sexuality in later life than those from earlier birth cohorts. A larger proportion of men (57% v 40%, P<0.001) and women (52% v 35%, P<0.001) reported very happy relationships in 2000-1 compared with those in 1971-2. Sexual debut before age 20 increased in both sexes: in men from 52% to 77% (P<0.001) and in women from 19% to 64% (P<0.001). CONCLUSION: Self reported quantity and quality of sexual experiences among Swedish 70 year olds has improved over a 30 year period.