In a still ongoing prospective longitudinal study, more than 500 children--a total birth-cohort in a Danish municipality--were followed from their 3rd to their 9th year of life by multiple impedance tests in order to investigate a number of factors concerning epidemiology and long-term impacts of otitis media with effusion. This is a report on the influence of otitis media with effusion early in life on reading achievement. The study revealed no difference in school-class level between the 9% of the children (n = 46) who constantly had abnormal tympanometry during a 6-month period at the age of 3, and the other pupils in the municipality. At the Silent Reading Test (OS-400), done on 40 of the 46 case-pupils the results did not differ from (1) the other pupils in the municipality, (2) from other pupils of the same sex in the same classroom, or (3) from individual control-pupils matched by sex, social group and classroom.