In recent years a variety of questionnaires has been used to identify subjects with psychological illness in both community and hospital settings. Most questionnaires, unfortunately, lack of clinical validity, and, to date, none has been validated for an Australian sample. The present study describes a validation of the General Health Questionnaire in a sample of general-practice patients in Sydney, and finds this instrument to be an efficient, reliable, and valid index of non-psychotic psychological impairment.