Increasing emphasis has been placed on the detection and treatment of hazardous and harmful drinking disorders, particularly among patients who are seen in primary care settings. In this review, we summarize the epidemiology and health-related effects of hazardous and harmful drinking and discuss current methods for their detection and treatment. Hazardous drinking is defined as a quantity or pattern of alcohol consumption that places patients at risk for adverse health events, while harmful drinking is defined as alcohol consumption that results in adverse events (e.g., physical or psychological harm). Prevalence estimates range from 4% to 29% for hazardous drinking and from less than 1% to 10% for harmful drinking. Data from several recent large prospective studies suggest that alcohol consumption in quantities consistent with hazardous or harmful drinking may increase risk for adverse health events, such as hemorrhagic stroke and breast cancer. Existing screening instruments, such as the Michigan Alcoholism Screening Test (MAST) or the CAGE questionnaire, while excellent for detecting alcohol abuse or dependence, should not be used alone to screen for hazardous and harmful drinking. The Alcohol Use Disorders Identification Test (AUDIT) is currently the only instrument specifically designed to identify hazardous and harmful drinking. Treatment of these disorders in the form of brief interventions can be successfully accomplished in primary care settings, as demonstrated by a number of well-conducted randomized trials. Given its proven efficacy in the primary care setting, we recommend routine application of this treatment approach.