This research examines the substance abuse severity problem of the male narcotics arrestees of Turkey within the framework of Akers' Social Structural and Social Learning (SSSL) model. The SSSL model is tested to understand the impact of social structural factors on drug abuse severity of narcotics offenders, in mediation of social learning process. The research design consists of secondary data analysis and modeling techniques to test the hypotheses pertaining to the SSSL model. The data, consisting of 1,647 male cases, have been obtained from the TUBIM Program. The U.S. ADAM Program year 2003 data including 6,730 cases have also been utilized with the purpose of observing the similarities and/or differences among substance abusers across the nations, as described in Chapter 5. Accordingly, the narcotics criminals of Turkey and the U.S. were compared in terms of demographic status, criminal background, substance abuse behavior and state of substance related treatment. Eventually, it was found that substance abusing populations across these two nations are significantly different. In the second phase of the study, Akers' SSSL model was developed and tested on the male narcotics offenders of Turkey. Structural Equation Modeling (SEM) analysis was used to test the hypotheses of the study. A model for the drug offenders whose last charge is drug related (substance abuse or substance distribution) was developed and the model's robustness was tested on those narcotics offenders who have reported committing property and violent offenses before the last charge. It is found that the impact of the social factors on drug abuse and dependence behavior through social learning constructs is non-significant except for the age variable for the drug related offenders subset. Furthermore, the impact of all social structural factors on the seriousness of substance abuse in the mediation of social learning constructs is insignificant for the property and violent offenders subset. Also, the social learning construct of the property and violent offenders' subset does not significantly influence the seriousness of substance abuse.