The informative content of summaries concerning 96 patients in whom the diagnosis of cancer of the breast was established in 1986 in local and regional hospitals in Denmark was investigated. The informative content of the summaries were illustrated by investigation of the extent to which the summaries contained information about the diagnosis, treatment, laboratory investigations, information to the patient and her relatives and information about contact with the general practitioner. In addition, summaries from the regional hospitals were investigated as regards information about the prognosis and the medical and sociomedical therapeutic plan. Information about the diagnosis, treatment, laboratory investigations and the medical therapeutic plans was, as a rule, provided in the summaries. Information about information to the relatives, prognosis and the sociomedical therapeutic plan for follow-up control by the general practitioner was scarcely ever provided in the summaries. Information to the patient was mentioned in less than half of the summaries from local hospitals and in less than 20% of the summaries from regional hospitals. This investigation reveals that the summaries lack valuable information.