School health records for a group of Danish school children, who started school in 1977, 1987 and 1997, were studied in order to evaluate hearing ability at the time of starting school and leaving school. One thousand, six hundred and five children who were evaluated by audiometry were included in the study. We found a higher prevalence of hearing loss in children who started school in 1987 and 1997 compared to those who started in 1977. The typical hearing loss was in the high frequencies. At the end of school the hearing ability of children who had started school in 1977 was just as poor as of that of those who had started in 1987. Whether this hearing loss may lead to poorer learning capacities in the afflicted children should be evaluated by further studies that include information on exposure to noise.