This article reviews the reliability and the validity of the (10-, 20-, and 28-item) Drug Abuse Screening Test (DAST). The reliability and the validity of the adolescent version of the DAST are also reviewed. An extensive literature review was conducted using the Medline and Psychinfo databases from the years 1982 to 2005. All articles that addressed the reliability and the validity of the DAST were examined. Publications in which the DAST was used as a screening tool but had no data on its psychometric properties were not included. Descriptive information about each version of the test, as well as discussion of the empirical literature that has explored measures of the reliability and the validity of the DAST, has been included. The DAST tended to have moderate to high levels of test-retest, interitem, and item-total reliabilities. The DAST also tended to have moderate to high levels of validity, sensitivity, and specificity. In general, all versions of the DAST yield satisfactory measures of reliability and validity for use as clinical or research tools. Furthermore, these tests are easy to administer and have been used in a variety of populations.