BACKGROUND: Unexpected failed mask ventilation can result in brain damage or death. The purpose of this study was to demonstrate that the tests for predicting difficult tracheal intubation can be used to predict difficult mask ventilation in Koreans. METHODS: One hundred ninety one patients were assessed before operation using the modified Mallampati test and by measuring the atlanto-occipital angle (AOA), thyromental distance (TM), hyomental distance (HM), sternomental distance (SM), and horizontal length of mandible (HLM). The mask ventilation grades and the laryngeal grades were determined. The sensitivities, specificities and positive predictive values of tests were calculated. RESULTS: Eleven patients (5.7%) had difficulty in mask ventilation and 8 patients (4.1%) had difficulty in intubation. AOA grade had the highest sensitivity and every tests had relatively high specificities for predicting difficult mask ventilation. CONCLUSIONS: The tests for predicting difficult tracheal intubation can be used to predict difficult mask ventilation.