One hundred and twenty-two children between 1 1/2 and 14 years of age with symptoms suggesting tonsillar obstruction have been investigated. Each patient's history was analysed and the symptoms scored according to their incidence and severity. In addition, the size of the tonsils was evaluated. Eighty-five patients were chosen for tonsillectomy. The children with signs and symptoms of tonsillar obstruction improved greatly immediately after tonsillectomy. Severe symptoms of obstruction were observed in children with nearly normal tonsil size, as well as in those with very large tonsils. It is therefore just as important to obtain a careful history as it is to evaluate the size of the tonsils before deciding about surgery.