The purpose of the study was to evaluate whether there is an association between early recurrent otitis media and later school achievement. A nation-wide, population-based random cluster sampling of 1708 children in 119 school classes was performed throughout Finland. Data were collected with questionnaires sent to the parents and teachers of the children. Teachers evaluated each child's performance at school, and the association between the number of episodes of early otitis media and school achievement was determined. Recurrent otitis media episodes before the age of 3 years associated significantly with lower performance in mathematical skills (risk ratios [RR] 1.2-1.4, 95% confidence intervals [95% CI] 1.0-1.7, P-values 0.04-0.02) and classroom concentration (RR 1.4, 95% CI 1.1-1.8, P-value 0.02) among the girls. The boys with recurrent otitis episodes performed more poorly in reading (RR 1.3, 95%, CI 1.0-1.6, P-value 0.05) and oral performance (RR 1.2, 95% CI 1.1-1.4, P-value 0.01). No association between otitis episodes after the age of 3 years and school achievement was found. Our findings suggest that recurrent otitis media episodes before the age of 3 years have adverse long-term consequences even when treated actively. Even though the risk ratios were low our finding is important because recurrent otitis media is a common problem during infancy and school achievement has many practical influences on a child's future.