A 30-year-old African female with established acquired immunodeficiency syndrome (AIDS) and no history of diabetes, presented in severe diabetic ketoacidosis (DKA). Blood pH was 6.96, serum bicarbonate 5 mmol/l, plasma glucose (PG) 33.0 mmol/l, and urine heavily positive for ketones. She responded to standard treatment and was established on twice-daily subcutaneous insulin. Four months later her insulin was stopped because of hypoglycaemic attacks on small doses. A glucose tolerance test (GTT) at 6 months postdiagnosis was normal (fasting PG 4.4 mmol/l and 2 h PG 7.5 mmol/l), and at 12 months random PG was 4.1 mmol/l and HbA1c 4.3%. The onset of her apparent Type 1 diabetes coincided with an HIV-associated cytomegalovirus (CMV) infection, and a reversible 'CMV insulitis' may be an explanation. Alternatively, the patient may have had what has recently been described as 'atypical diabetes' in African or Afro-Caribbean diabetic patients. Here resolution of diabetes may occur after presentation, though complete return to normoglycaemia after true DKA is very unusual.