A study was undertaken in order to examine the quality of management of diabetic ketoacidosis (DKA) in a teaching hospital and to assess whether the introduction of clinical guidelines contributed to a satisfactory outcome. Data on presentation and management of 71 cases of DKA admitted in one calendar year (1994) were collected and analysed. Comparing the data to standards set in guidelines, inadequacies of clinical management were identified including delay in initiation of intravenous fluid replacement (greater than 30 min) and intravenous insulin (greater than 60 min) in 70% and 69% of cases, respectively; under-replacement with intravenous fluid in the first 24 h (less than 6.5 l) in 70% of cases, and insufficient intravenous potassium replacement (less than 70 mmol) in the first 24 h in 70% of cases. Suboptimal management of DKA may have contributed towards death in one of the three fatalities, and to morbidity in other patients. In 22.5% of cases (group 1) in whom the guidelines were alleged to have been followed, intravenous fluid, potassium, and insulin had been administered earlier and in larger quantities compared to the remaining cases (group 2). However, in most cases in group 1 the standards set by the guidelines were unfulfilled and the incidence of hypokalaemia, hypoglycaemia, and duration of in-patient stay did not differ from group 2. The treatment of DKA by non-specialist general medical staff in a large teaching hospital was frequently inadequate and was associated with significant mortality and morbidity. The introduction of guidelines had moderately influenced the process of managing DKA but not the outcome, probably because of the low rate of their implementation by junior doctors.