The aim of our study was to examine the quality of life of opiate addicts and to determine potential differences in quality of life depending on certain factors. The study included 43 opiate addicts who were treated stationary, as an outpatient, and in the day hospital at KBC Sestara milosrdnica, Psychiatric Clinic Zagreb. There were 33 males, and 10 females who participated in this study, most of whom were between 30 and 40 years of age. Quality of life was assessed with the WHOQOL-BREF questionnaire, which includes physical and psychological health, social relationships, and quality of the environment. Participants filled out one more questionnaire, which evaluates socio-demografic data and the use of drugs. That questionnaire was designed for the purpose of this research. Quality of life of opioid addicts differs from the one of healthy people, but it is no different then the quality of life of people who suffer from some illness. No statistically significant difference was found in quality of life depending on the number of rehabs, nor depending on the frequency of the consummation of the main drug of addiction. Psychoactive substances (cocain, stimulants, sedatives, hallucinogens and cannabinoids) which addicts consume casually along the main drug of addiction, didn't generate any significant difference in quality of life. Quality of life of participants in this study doesn't significantly differ depending on existance of the support from friends. Family support, and family members mental health affects quality of the environment in which opioid addicts live.