Illegal substance use is a, serious problem all over the world. In order to effectively combat substance abuse it is important that both the particular features of drug users and the culture-specific risk factors that go along with drug abuse be identified. The present study was carried out in Bursa, Turkey, in order to document annual changes in the frequency of felons arrested of narcotics offenses and to establish the socio-demographics of these narcotics felons. Among the 2,230 narcotics felons reviewed, 24.3% had been charged with drug dealing but not consumption (profit-driven felons [PDFs]), 19.0% were narcotics felons charged with both dealing and consumption ([hard core drug users HCDUs]), and 56.7% were narcotics felons charged only with consumption and possession (not so hard core drug users [NHCDUs]). The NHCDUs were younger (< 30 years) than both the HCDUs and PDFs, while most of the PDFs and HCDUs were married. Despite the fact that the male/female ratio of the Bursa population was nearly I : 1 for the past 30 years, 93.0%, 95.0% and 96.0% of the PDFs, HCDUs, and NHCDUs, respectively, were male. It was also found that the most commonly used illicit substance in Bursa over this period of time was cannabis. Over the course of the 30-year period examined, the annual incidence rate of narcotics felons arrested increased from 0.4257 per 10,000 to 1.2389 per 10,000. Determining the socio-demographic characteristics of HCDUs and NHCDUs would be useful in preventing substance use before substance users become addicted.