Recognising the widespread role of traditional birth attendants (TBAs) and herbal practitioners (HPs) in health care at community level in Nigeria, we set out to assess their knowledge, attitudes and practices in relation to HIV infection and prevention. Questionnaires were administered to a convenience sample of 189 participants in 20 local government areas of Lagos State. We found that knowledge of modes of transmission of HIV was less than adequate and included lack of knowledge of the existence of HIV/AIDS amongst some practitioners, claims for the ability to treat HIV/AIDS, failure to name major avenues of transmission and confusion of HIV/AIDS with other conditions. The use of measures to prevent infection of clients and themselves showed that normal standards of infection control are not adhered to. Considering that as many as 60% of children born in Nigeria are delivered by traditional birth attendants and that use of the services of herbal practitioners extends across the entire society in both rural and urban settings, this is seen as reason for concern. It is suggested that better incorporation of TBAs/HPs into the well-developed primary health care system offers not only a way of overcoming the risks of infection posed by traditional health practices but also offers an opportunity to extend the reach of voluntary counselling and testing and prevention of mother-to-child infection programmes. The research has shown the need for appropriate training of TBAs, to enable them to recognise the risk of HIV infection in their own practices and to encourage them to adopt universal precautions against spreading infection. We also recommend that they be more extensively integrated as primary health care workers in VCT and PMTCT programmes in Nigeria. We further suggest that referrals made between the traditional practitioners and professional health care providers can be an effective and successful element of HIV/AIDS prevention and control programmes.