BACKGROUND: /st> Estimation of teeth-to-vallecula distance would facilitate the selection of properly sized oropharyngeal airways in young children. The aims of the present study were to measure the teeth-to-vallecula distance and to create an algorithm to predict this distance based on anatomical landmarks and patient characteristics in children. METHODS: /st> Two hundred children, aged 1-9 yr, undergoing elective surgery were investigated. After induction of general anaesthesia, the distance from the teeth to the vallecula was measured using a laryngoscope with a straight blade. After intubation, the distances from the mouth angle to the mandible angle and the tragus of the ear were measured with a tape measure. RESULTS: /st> The teeth-to-vallecula distance was significantly correlated with the age, weight, height, and external measurements (P<0.001). By stepwise multiple linear regression analysis, a formula was obtained for the teeth-to-vallecula distance (cm)=3.998+0.017×age (months)+the mouth-to-mandible distance×0.286 with a high coefficient of determination (r(2)=0.764). CONCLUSIONS: /st> The teeth-to-vallecula distance can be predicted using the age and the mouth-to-mandible distance in young children.