A thorough retrospective review of all case notes of patients attending the outpatient clinics in a newly opened acute care psychiatric hospital in Jeddah identified 485 patients with substance abuse during a period of one year. Heroin and alcohol were the most common substances abused. Comparison of the drug history and sociodemographic characteristics of our patients with three similar studies from Western countries revealed some significant differences. Low female ratio, significant difference in age group, and generally higher daily regular intake are some of the differences.