The health problems of 117 children with Down's syndrome were identified through a questionnaire to their mothers, as part of a wider study of the process of adaptation among families in the Manchester Down's Syndrome Cohort. At the time of the present study, the children were all of school age: mean age 9 years 2 months, range 6 to 14 years. Results from the current study are compared with that from earlier studies involving these children. Vision and hearing problems and respiratory infections were identified as the most common health problems, affecting a large percentage of the children. While a high proportion had been hospitalized and had undergone operations, the proportion of children who had missed more than 4 weeks of schooling in the previous 12 months was not high compared to the general child population. Equally, the numbers who had suffered accidents did not appear unduly high. Poor child health was found to be associated with a higher level of behaviour problems and increasing maternal stress over time. The need for health screening to continue during this period of childhood is identified.