Background and objectives. Diabetes affects approximately 1 million South Africans. Hospital admissions, the largest single item of diabetes expenditure, are often precipitated by hyperglycaemic emergencies. A recent survey of a 200-bed hospital, serving approximately 1.3 million Cape Town residents, showed that hyperglycaemic emergencies comprised 25.6% of high-care unit admissions. A study was undertaken to determine the reasons for, and financial cost of, these admissions. Methods. All hyperglycaemic admissions during a 2-month period (1 September-31 October 2005) were surveyed prospectively. Admissions were classified using the American Diabetes Association classification of hyperglycaemic emergencies. Demographic data, and the reason for, duration of and primary outcome of admission, were recorded. The following costs per admission were calculated using public-sector pricing: (i) total costs; (ii) patient-specific costs; (iii) non-patient specific costs; and (iv) capital costs.