Screening tympanometry was performed in 278 healthy 2-year-old children (556 ears) born the first 10 days of every month in 1976 in two municipalities from Copenhagen County. A middle ear pressure between 0 and -99 mm H2O was found in 49.6%, between -100 and -199 in 19.4%, between -200 and -300 in 20.1%, and flat curves in 10.8%. The latter group also otoscopically gave evidence of middle ear effusion. The results reveal the highest incidence of tubal dysfunction and middle ear effusion for this age group in contrast to any other age group. However, a large spontaneous recovery from secretory otitis was also noted. No differences were found between sexes, right ear/left ear, the socio-economic factors, or whether the children lived in houses or apartments. Children who were nursed in public nurseries had a significantly higher incidence of secretory otitis than those nursed in private nurseries or at home.