BACKGROUND: The Patient Protection and Affordable Care Act of 2010 supports integration of substance abuse interventions and treatments into the mainstream health care system. Thus, effective screening and intervention for substance use disorders in health care settings is a priority. OBJECTIVE: This paper reviews the prevalence of alcohol and drug use disorders (abuse or dependence) in primary care settings and emergency departments, as well as current screening tools and brief interventions. METHODS: MEDLINE was searched using the following keywords: alcohol use, alcohol use disorder, drug use, drug use disorder, screening, primary care, and emergency departments. Using the related-articles link, additional articles were screened for inclusion. This review focuses on alcohol and drug use and related disorders among adults in primary care settings. CONCLUSION: Screening, brief intervention, and referral for treatment are feasible and effective in primary care settings, provided that funding for screening is available, along with brief interventions and treatment facilities to which patients can be referred and treated promptly.