The case is presented of a 34-year-old man, an insulin-dependent diabetic, who was found decomposed in his apartment. The victim had been recently discharged from a mental hospital and was to be monitored by the community's mental health personnel. While the autopsy revealed little in the way of disease, toxicological studies yielded a blood acetone level of 0.070 g/dl and a urine acetone level of 0.086 g/dl. The medical examiner ruled the cause of death diabetic ketoacidosis. To support this conclusion in the absence of a vitreous humor glucose concentration, 18 well-documented cases of diabetic ketoacidosis were reviewed, and acetone concentrations were compared with the acetone concentrations found in the presented case.