A study of the prevalence of atopic disorders among 15-16-year-old teenagers was carried out in a coastal urban town in south-western Finland. Altogether, 1712 children were found in that age group, all previously examined by a pediatrician. Each child who had present or previous allergic diseases was invited for a detailed study, a total of 434 (25%) pupils. Of these patients 416 (95.8%) participated in clinical examination and skin testing. The prevalence of atopic diseases was 21% in the studied group; atopic eczema was found in 9.7%, allergic rhinitis in 14% and asthma in 2.5%. Of subjects who had rhinitis, 38% also had atopic eczema, while rhinitis--as the only symptom--was found in 8.8%. Figures obtained from this survey suggest that the prevalence rates of atopic diseases are about the same as found 10 years ago in Finland and they correspond also with other recent reports.