Abstract: ObjectiveTo identify influencing factors of human immunodeficiency virus/acquired immune deficiency syndrome(HIV/AIDS)related high-risk behaviors among drug users receiving methadone maintenance treatment (MMT)in Guangdong province.MethodsTotally 7 288 patients from 14 community-based MMT clinics in Guangdong province were investigated with a questionnaire survey at enrollment.Logistic regression analysis was used to analyze the influencing factors of high risk behavior.ResultsThe proportion of the patients with injecting drug use during last month was 80.24%,and that of condom use in the latest sexual behavior was 42.53%.The point prevalence of HIV infection was 7.46%and that of hepatitis C virus (HCV)infection was 78.96%.HIV infection (odds ratioOR=3.54),HCV infection (OR=3.94)and long history of drug use (OR=1.78)were risk factors of drug injection behavior.Having a job (OR=0.85)and higher education level (OR=0.83)were protective factors of drug injection behavior.The patients having good relationship with their families (OR=1.42),with HIV infection (OR=1.46)and at older age (OR=2.63)were more likely to use condom in the latest sexual behavior.In contrast,married participants(OR=0.78)tended to have unprotected sexual behavior among the drug users.ConclusionHIV infection,HCV infection and long history of drug use are risk factors for high-risk behaviors related to HIV/AIDS.Having good relationship with their families,with higher education level and having job are protective factors of the high-risk behaviors among drug users.