Studies report substantial sexual behaviour change in Africa in response to HIV/AIDS. Generally there seems to be an increase in condom use and a reduction in partners, with men reporting more change than women. However, it is not only important to know whether people are changing their sexual behaviour but also their reasons for changing and the consistency and extent of change. Between 1996 and 2000 a study involving 196 respondents was carried out in rural southwest Uganda to investigate the exact nature of behaviour change and the reasons for change or lack of change since people became aware of HIV/AIDS. Data were collected from three rounds of questionnaire surveys, four rounds of open in-depth interviews, six rounds of semi-structured interviews and from informal conversations and participant observation. In order to obtain a comprehensive assessment of behaviour change the data for each participant from all sources were compared and discrepancies were then followed up by re-interviewing participants. After triangulation between all sources of data, 48% of respondents had ever used a condom. Condom use in 76% of all cases was at least partly AIDS related, while 19% was exclusively for protection against HIV. Condom use tended to be sporadic: only 13% of condom users currently used a condom regularly and most of this use was for family planning. After triangulation, 45% had reduced the number of sexual partners. Of all partner reductions, 93% was at least partly AIDS related; 29% was exclusively to avoid HIV. Half of those who had reduced the number of partners either stuck to one partner or abstained. Men reported more change than women. Of those who reported no partner reduction, 89% could not reduce the number of partners because they already had only few or a single partner or abstained; most of these were women. Most of those who could change their sexual behaviour had already changed, though the degree of change (particularly condom use) was often minimal. Not only behaviour change, but also the maintenance of safe behaviour is important. Also, understanding reasons for change and extent and consistency of change are important when planning and evaluating interventions.