for several factors, not yet fully explained until now, infant deglutition may persist after changing the primary teeth and such swallowing is classified as atypical swallowing. possible causes: finger sucking, bottle feeding, sucking the tongue and mouth breathing. there is no consensus about the etiology of atypical deglutition. objective: the aim of this study was to compare the oropharyngeal space in side-view radiographs of children with atypical deglutition and normal deglutition. methods: retrospective study, by means of cephalometric analysis of side-view radiographs, measuring the anteroposterior distance of the lumen of the airway in two groups: 55 cephalograms from the experimental group (with atypical deglutition) and 55 side-view radiographs from the control group (normal deglutition). measurements from the groups were compared using mann-whitney u test and a p value <0.05 was considered as an indication of statistical significance. results: the median in the control group was 10 mm and in the experimental group it was 7 mm, with a statistically significant difference (p <0.001). conclusion: the oropharyngeal space is reduced in the group with atypical deglutition.