The HIV and STIs epidemic in China has had a significant impact among China's ethnic minorities. However, the official traditional approach, which has used an anti-epidemic social campaign, has not paid any attention to the diversity of cultural backgrounds of the many ethnic minority groups. This study carried out in Sichuan Province is the first to explore how to use cultural resources for developing an effective strategy for promoting HIV prevention in different cultural groups in China. One hundred and fifty male volunteers drawn from the Yi (50), Tibetan (50) and majority Han (50) cultural groups were assigned to a direct training programme. After training, these participants spread safe sex messages to other contacts who became an indirect peer diffusion group. A third group of 150 male volunteers from the same three cultural groups but from another relatively comparable community acted as controls. Each participant was interviewed before and after the intervention to assess knowledge, attitudes and behavioural intentions regarding HIV/AIDS prevention. The study examined the cultural appropriateness and effectiveness of peer-led health message diffusion in promoting condom use through a traditional oral communication approach from the direct training groups to the indirect intervention groups and broad peer networks within the Yi, Tibetan and Han cultural communities. Key findings showed that the peer-based oral communication strategy was effective for encouraging condom use with casual sexual partners in both the direct training group and the indirect peer diffusion group in all three cultural groups. There was no significant change in any of the comparison groups. Although change in the majority Han cultural group was generally greater than in the ethnic minority groups, the results clearly suggest that the methods can be successfully adopted to promote safe sexual behaviour in different cultural groups of China.