The Alcohol Use Disorders Identification Test (AUDIT) is a 10-item questionnaire designed to screen for hazardous and harmful alcohol consumption. We examined its ability to predict alcohol-related illness and social problems, hospital admission and mortality over a 2-3-year period. At initial interview, 330 ambulatory care patients were assessed using a detailed interview including the AUDIT questions and laboratory tests. After 2-3 years, 250 (76%) subjects were reassessed and their experience of alcohol-related harm determined. Of those who scored eight or more on AUDIT at initial interview, 61% experienced alcohol-related social problems compared with 10% of those with lower scores (p < 0.0001); they also had a significantly greater experience of alcohol-related medical disorders and hospitalization. AUDIT score was a better predictor of social problems and of hypertension than laboratory markers. Its ability to predict other alcohol-related illnesses was similar to the laboratory tests. However, gamma glutamyltransferase was the only significant predictor of mortality. We conclude that AUDIT should prove a valuable tool in screening for hazardous and harmful alcohol consumption so that intervention can be provided to those at particular risk of adverse consequences.