The presentation is comprised of three parts. Part 1 reviews the clinical, scientific, and ethical bases for integrating the prevention, treatment and management of substance use disorders within general medical settings. Part 2 examines available evidence suggesting why such an integrated approach has the potential for improved effectiveness and reduced costs of care for individuals with primary substance use problems. Part 3 reviews the prevalence and effects of secondary substance use problems within the large populations of patients with various, primary chronic illnesses. The presentation concludes with an argument that the most significant potential for benefits from the described integrated approach will accrue to general healthcare, through elevation of clinician diagnostic and treatment management skills, improved effectiveness and reduced untoward effects from contemporary treatments and significant reductions in costs of care.