The Xinjiang Uyghur Autonomous Region has a firmly established HIV epidemic among its intravenous drug user (IDU) population. Local sex workers were also found to be positive in 1998. A descriptive, cross-sectional survey of knowledge about HIV/AIDS and attitudes among consecutively selected pregnant women was conducted November 2005 in Aksu Prefecture, north-western China, with a population on 2 million with about 25 000 pregnancies per year. A total of 291 pregnant women participated. We found a limited knowledge on mother-to child transmission with several misconceptions. The AIDS campaigns have been successful in making all the women aware of HIV as a sexually transmitted disease. However, the common belief that social contact causes transmission gives a high risk that patients are stigmatized. Obviously, it is important to design HIV information strategies that target pregnant women in north-western China.