Abstract: Objective To survey attitude and knowledge about AIDS in female sex workers(FSW) and injection drug users(IDU) in Panyu district of Guangzhou and to provide in formation for further behavior intervention.Methods To tally 844(407 FSW and 437 IDU) respondents were selected with random sampling from Panyu district,Guangzhou city in July 2010.The information on demography, medical treamtent, AIDS-related knowledge, and high-risk behavior were collected with a face-to-face questionnaire survey.Results The integrated awareness rate of AIDS awareness was 56.8% and 52.6% for FSW and IDU, without significant difference between the two groups(X²=1.447, P=0.229).There were 19.4% of FSW not using condom during their sexual behavior each time.There were 27.5% of the IDU having the history of sharing syringe.The FSW and IDU got AIDS knowledge mainly through TV program (85.5% for FSW and 89.5% for IDU).Age was the main factor affecting condom use in commercial sex behavior among the IDU (odds ratio=2.433, 95% confidence interval: 1.162-5.095).Conclusion There is a high risk for HIV infection and prevalence of AIDS among FSW and IDU in Guangzhou city and effective intervention should be carried out among them.