This study shows a Behavior Modification Program (BMP) designed specifically to deal with adult drug abuser in Saudi Arabia. BMP involves multi-stage process in which successively more difficult behaviors are attained and maintained on reinforcement while drug-related behaviors are progressively reduced. The results of this program are compared against control group. Compared to control group, BMP group had higher mean age, more years of education and higher percentage of separated, divorced and widows. Only 27.7% of the study group and 44.5% of the control group were employed. The great majority of both groups were current smokers. 52.4% of study group had at least one co-morbid disease, compared to 30.3% in the control group (P<0.001); they also had significantly higher rates of tuberculosis (p=0.004), and anti-HCV (p<0.001). The percentages of all drugs were higher among patients in the study group; amphetamine, cannabis, and alcohol had the highest percentage in both groups. Significant effects were achieved on all criteria over control group. The behavior modification approach described is offered as a viable alternative to traditional probation methods.