To determine intellectual and linguistic sequelae of middle ear disease, 207 children were randomly selected from a cohort of 498 followed prospectively from birth until age 7 years. After controlling for confounding variables, estimated time spent with middle ear effusion (MEE) during the first 3 years of life was significantly associated with lower scores on tests of cognitive ability, speech and language, and school performance at age 7 years. The adjusted mean full-scale WISC-R were 113.1 for those with least time with MEE, 107.5 for those with moderate time, and 105.4 for those with most time. Similar significant differences were found for verbal and performance IQ scores. For the Metropolitan Achievement Test, we found that middle ear disease in the first 3 years of life was associated with significantly lower scores in mathematics and reading. Similar differences were found for articulation and use of morphologic markers. After considering time spent with MEE during the first 3 years of life, time spent after age 3 years was not a significant predictor of scores on any of the tests administered.