Ten years follow-up of 48 patients (33 boys, 15 girls) with middle ear effusion treated by adeno-tonsillectomy, antral lavage and paracentesis is presented. Using the modified but stricter classification of Tos and Poulsen, the results compare well (Table V). Agreement between otoscopy and impedance measurement was remarkably high. It was noted that the greater the number of repeated paracenteses, the higher the compliance rose above normal, but there was no relation to the viscosity of the fluid found. In ears in which grommets were used, only in 10 per cent was the tympanic membrane found to be normal at otoscopy and impedance measurement, as compared with 55 per cent of ears which did not receive a ventilation tube. Poor pneumatization of mastoids indicated a poor prognosis. Sinus infection was present in the majority of cases treated. Another finding of interest was a patulous Eustachian tube in six patients--one bilateral and five unilateral. Despite the vast amount of literature published describing various combinations of treatment in the management of middle ear effusion, the challenge remains. Long term follow-up results for various methods employed would be welcome.