The HIV/AIDS epidemic in Vietnam is still at concentrated stage, mostly among injecting drug users (IDUs). Despite of existing drug treatment methods, the relapse among this group is high. This paper describes some available methods of drug treatment and identifies influencing factors on the relapse among IDUs. Qualitative research was conducted from April to September 2010. There were 50 participants in the study, of which 37 IDUs. The results showed that all patients have experiences in different methods of drug treatment programs, including those at the education and rehabilitation (06) center, community drug treatment program, private settings, home detoxification program. Patients were mainly treated by cutting addiction in the first days, which should be easy to relapse. Factors influencing relapse rate were: the lack of motivation to quit drugs, lack of care from family, inferiority complex, having a wide drug network and friends, were dragged into the drug use after treatment, no employment. The Methadone substitution treatment program is effective, especially in reducing the opiate users.