Hospital admissions data for 1981 reveal that, for the population of East Anglia, 1.6% of hospital bed days were attributed to diabetes mellitus as the principal cause for admission. Admissions for diabetes without complications or with ketoacidosis or other coma accounted for about 60% of bed days while the other specified complications of diabetes accounted for the remainder. Admissions with diabetes as a subsidiary diagnosis accounted for 2.6 times as many bed days as those for which the disease was the principal diagnosis. Ischaemic heart disease or cerebrovascular disease was recorded as principal diagnosis significantly more often than would be expected from the general population experience, particularly for female diabetics. On an average day, 5.6% of beds were occupied by diabetic patients. The diabetic population of East Anglia used, on average, 5.1 hospital bed days per person year compared with 1.1 days for the non-diabetic population.