Objective To investigate the risk factors for HIV and HCV infections in patients receiving methadone maintenance treatment (MMT) in Kaiyuan,Yunnan province.Methods Patients receiving MMT in June 2014 in Kaiyuan were included in this study.The prevalence of HIV and HCV infections were calculated and logistics regression analysis was conducted to identify related risk factors.Results In June 2014,275 patients received MMT,their average duration of MMT was 4.0 ± 2.4 years.The overall HIV infection rate was 51.6％ (142/275).All the HIV infection occurred before MMT.In 275 patients,222 were infected with HCV before MMT,and 17 new HCV infections occurred during MMT.And the HIV/HCV co-infection rate was 49.1％.The results from multivariate logistic regression analysis indicated that the risk of HIV infection was higher in those who were unmarried/divorced/widowed (adjust OR=2.39,95％CI:1.29-4.43) and injecting drug users (adjust OR=5.52,95％CI:2.69-11.35),sharing needles with others (adjust OR=2.32,95％CI:1.04-5.18) and had longer history of drug use.For HCV infection,injecting drug use was the independence risk factor(adjust OR=11.54,95％CI:4.79-27.80).Conclnsion The prevalence of HIV,HCV infections and HIV/HCV co-infection in patients in MMT clinic were higher in Kaiyuan than in other areas in Yunnan.More intervention should be given to the patients who had history of injecting drug use.