A peer-education HIV/AIDS prevention programme for bar-based sex workers and their potential clients (long-distance truck drivers) in Malawi was evaluated for impact. A mixed method approach was used, the tools being structured questionnaires and focus group discussions. The results showed that in the active districts, the presence of sex worker peer educators led to a increase in condom use with paying partners (90.3 compared to 66.7 and 76.3% in the two other groups--non-active and average) and increased condom distribution. Condom use with regular non-paying partners of sex workers had, however, not increased since the baseline data. The truck driver peer educators were found to be generally inactive but companies where training had occurred were more likely to encourage and distribute condoms. The qualitative data gave a more in-depth view of several areas for concern: the reasons for the non-use of condoms with non-paying partners; acceptance of educators by their peers; and the sex workers' and truck drivers' criteria for condom use based neither on knowledge nor on their own risk awareness. These issues need to be explored further.