This study assessed the characteristics and motivation for substance use among addicts referred to the Shiraz Self-identified Center, an out-patient treatment facility. Data were gathered by a semistructured interview from 306 consecutive addicts seeking treatment and referred from July to September, 1998. Their mean age was 37 yr., and the majority (73.9%) were married. Of these addicts, 28.4% were workers, 13.4% drivers, and 11.4% were unemployed. Modeling or social pressure (43.1%) was identified as the first and enjoyment (fun) was the second most common reason given for opiate use. The majority (97.1%) used opium and 71.9% used alcohol; however, only 2.6% reported current use of alcohol. Other subjects were current users of cigarettes (72.2%), opium (67%), heroin (35%), hashish (2%), hallucinogens (0.3%), and cocaine (0.3%). The most common reason given for currently using opiates was habit (56.5%). About 36% of the subjects reported that they had frequently used opiates for more than a decade. These findings are quite different from those carried out in the West, although there is some overlap. Cultural attitudes toward drug use likely affect the types and amount of use.