General practitioners have the potential to treat patients with alcohol problems effectively. Despite the medical implications of excessive alcohol intake, it appears that general practitioners are not sufficiently aware of the drinking habits of their patients. The aim of the study was to investigate the accuracy of 56 randomly chosen general practitioners in detecting which of their patients had a high alcohol intake. Altogether, 2081 patients were recruited in general practitioners' waiting rooms, where they answered questions about their drinking habits. After the consultations general practitioners were asked to indicate the patients' levels of alcohol intake. The results showed that general practitioners correctly identified only 27.5% of patients who were classified as "high risk" drinkers, using Australian Medical Association criteria. They correctly identified only 45.2% of patients who were classified as "moderate to heavy" drinkers, defined by them as drinkers who consume four or more standard drinks a day. These findings have important implications for clinical practice since they indicate that general practitioners are failing to perform adequately in an important area of preventive medicine. This issue needs to be addressed in undergraduate and postgraduate medical education.