Alcohol is the most commonly abused substance yet alcoholism is frequently undiagnosed. The misuse of alcohol is common and frequently an occult problem. More than 10% of current drinkers meet diagnostic criteria for alcohol abuse or dependence while the lifetime prevalence for these conditions in outpatient settings ranges from 16 to 36 percent. Long-term, heavy drinking is associated with significant morbidity, mortality, and economic costs. Clues to alcohol use can be discovered from a patient's history and physical stigmata. Validated screening instruments such as the Alcohol Use Disorders Identification Test (AUDIT), CAGE Questionnaire, and Brief Michigan Alcoholism Screening Tests help confirm the clinical suspicion of alcohol dependence. Laboratory abnormalities of mean corpuscular volume, gamma-glutamyl transferase, alkaline phosphatase, or alanine amino transferase levels are non-specific indicators of possible alcohol-induced liver impairment. Newer, less well-known FDA-approved biochemical markers such as the Carbohydrate Deficient Transferrin and the Early Detection of Alcohol Consumption test may also be used to detect heavy alcohol abuse and to monitor relapse episodes. Brief interventions are successful, making identification and diagnosis a vital role for the family physician. Improved awareness of alcohol misuse, increased use of screening tools, and the appropriate use of biochemical markers will facilitate early intervention and successful management of patients with alcohol use disorders.