Children, who were tonsillectomized because of sleep apnea were examined with respect to facial growth and dental arch morphology. Dental casts and lateral roentgencephalograms were analysed before surgery and two years after tonsillectomy. The findings were compared to data from children without tonsillary obstruction. A higher proportion of malocclusion than normal, especially open bite and crossbite, was noticed before surgery. Two years after surgery, 77% of the open bites were normalised and 50-65% of the buccal and anterior crossbites. The best results were seen in children operated before the age of 6.