A 6-week-old girl, the first child of non-consanguineous parents, was admitted to the hospital for evaluation of vomiting. She was small for gestational age (1500 g). On admission, she weighed 1830 g, and appeared dehydrated. The blood glucose was 880 mg/dL. Insulin and C-peptide levels were <1 microIU/ml and 0.1 pmol/L, respectively. Antibodies of diabetes were negative. The serum triglyceride level was markedly elevated (5322 mg/dL). After a few days of insulin therapy, the triglyceride levels dramatically decreased, but cholestasis persisted. A liver biopsy revealed diffuse iron deposition and the diagnosis of neonatal hemochromatosis was established. In neonatal hemochromatosis, diabetes may occur as a result of iron deposition in the pancreas. The coexistence of neonatal diabetes secondary to neonatal hemochromatosis with a fatal course during the infancy period has not been previously reported. In this report, an infant with neonatal diabetes secondary to neonatal hemochromatosis is presented as the first case in the literature involving the coexistence of these two conditions.