We report the case of an otherwise healthy 11-year-old girl who died suddenly of previously undiagnosed diabetes mellitus type I, following a 2-day minor upper respiratory infection. Insulin dependent diabetes mellitus (IDDM) is a rare cause of sudden death of apparently healthy children. This report demonstrates a recommended diagnostic pathway for IDDM from the substantiation of vesicular fatty liver to specific pancreatic histological and histochemical changes.