Longitudinal changes and cohort differences from 1979 to 1989 in the use of prescribed and non-prescribed medical drugs were examined and the connections of drug use to various background variables were analysed in the framework of the Tampere Longitudinal Study of Ageing. In the longitudinal study random samples of men and women born in 1900-09 and 1910-19 (738 persons) were interviewed in 1979 and the survivors (62%) were interviewed again in 1989. In the cohort comparison the 60-69-year-olds studied in 1979 (364 persons) were compared with the 60-69-year-olds in 1989 (395 persons). In the longitudinal setting the number of prescribed drugs increased. In 1989 2 or 3 in 10 persons used at least five prescribed drugs simultaneously. In the cohort comparison there were no differences in the number of prescribed drugs between the two groups of 60-69-year-olds. Use was connected with multimorbidity and poor self-rated health. Both the longitudinal comparison in the group born in 1910-19 and the cohort comparison revealed a significant increase in the use of non-prescribed drugs. The use of analgesics was connected with sex, occupational class, self-rated health and feelings of loneliness. In the use of vitamins, no connection was found with health variables, but they were mostly used by white-collar employees and women. However, when all these variables were controlled for, both analgesics and, in particular, vitamins were used more in 1989 than in 1979. The results suggest that the increase in the use of non-prescribed drugs is mainly due to social and historical factors, by changes both in drug policies, health culture and health behaviour of elderly persons.