Abstract Identifying common characteristics of treatment clients helps to better design assessment, treatment, and rehabilitation strategies. For 2 years, adult inpatient clients admitted to a private Egyptian hospital were systematically assessed for substance abuse (N = 324). The clients were 91.4% male and 91.9% Muslim. Families supported 48.9% of the clients. Only 19.2% of the men and one woman were married. Cannabis (93.4%), alcohol (89.7%), psychotropic medications (80.9%), and heroin (78.4%; of those, 84.6% by injection) were the most common substances used recently. Anxiety (80.1%) and depression (77.4%) were common in the clients. Our study highlights mental health problems and family context of substance abuse treatment. It also underscores the few women receiving treatment. We recommend interventions to improve access and reduce harm associated with substance use.