Alcohol abuse is one of the factors considered when deciding whether to grant a security clearance. Individuals involved in the security clearance process should be aware of the prevalence of alcohol abuse in the overall population, indicators of alcohol abuse, the relationship between alcohol abuse and other behaviors of security interest, and the effectiveness of alcohol abuse treatment. About 10 percent of adult Americans have a serious alcohol problem. Excessive alcohol consumption may impair judgment and increase the risk of accidental, careless, or even deliberate disclosure of classified information. A four- question test known as the CAGE questionnaire has been used successfully to identify persons who need a more comprehensive assessment for alcohol problems. A positive response to any one of the four questions on drinking behavior should raise suspicions of an alcohol problem. Indicators of alcohol abuse are discussed, including arrest for driving while intoxicated, family history, and increasing tolerance for alcohol. Consideration is given to the prevalence of alcohol use and abuse; differences in alcohol consumption by age, sex, race, and region of the United States; the relationship between alcohol and other problem behaviors, such as mental and emotional disorders, crime, and spouse abuse; and the treatment of alcohol abuse and alcoholism. 53 references, 1 table, and 10 figures