The Abbreviated Mental Test is a useful screening test for abnormal cognitive function in the elderly patient. It is widely used in UK geriatrics practice. A modified local version of the Abbreviated Mental Test is also commonly used in Hong Kong. In the present study, the local version of the 10-question Abbreviated Mental Test was validated against clinical diagnoses of normal/abnormal cognitive function (by DSM III R criteria). Sixty-nine patients (aged 65 years and older) referred to the Acute Geriatric Assessment Team at the Queen Mary Hospital were assessed. Nine patients (13%) were excluded because of language barrier, deafness, dysphasia and/or severe dysarthria. Sixty patients completed the test and the clinical assessment. An incorrect answer in each of the test items was found to be significantly associated with abnormal cognitive function (P<0.005). For the Abbreviated Mental Test score, the best cut-off point was found to be six (below six was considered abnormal); this yielded a sensitivity of 96% and a specificity of 94%.