Aims: While past research has shown that school performance is associated with some specific health outcomes in adulthood, few studies have taken a general approach to the link between school performance and adult disease. The aim of the present study was therefore to investigate sixth grade school performance in relation to disease-specific hospital care in adulthood and, moreover, to examine whether other conditions in childhood could account for any such associations. Methods: The data used was the Stockholm Birth Cohort, consisting of 14,294 individuals born in 1953. Associations between school performance and disease-specific hospital care were analysed by means of Cox regression. Results: Poor school performance was shown to be linked to a variety of diseases in adulthood, e.g. drug dependence, stomach ulcer, cerebrovascular diseases, and accidents. Some differences according to gender were found. Most associations, but not all, were explained by the simultaneous inclusion of various family-related and individual factors (e.g. social class, cognitive ability, and behavioural problems). Conclusions: In sum, the results of this study suggest that poor school performance may be an essential part of risk clustering in childhood with important implications for the individual's health career.