Repetitive screening tympanometry performed in 240 healthy 2-year-old children showed that tympanometric conditions are significantly better in the summer season than in the spring or winter. A very large tendency to spontaneous normalization of the tympanogram type B was demonstrated. Only 16% of the ears that had type B at the first investigation in November had the same type in August. Simultaneous with the normalization of some ears others deteriorated, thus in November type B tympanogram was found in 12%, in February 14.6%, in May 11.3%, and in August 7.2% of all ears investigated. Due to the large variability in the tympanometric conditions which are predominantly caused by catarrhalia, 28.6% of the ears have had type B tympanogram at least once during the period from November to August, while only 1.6% have had type B at all four investigations. The large spontaneous recovery of secretory otitis, demonstrated in the present study, indicates that the child should be observed for a period before implementation of surgical treatment.