RESUMEN
A female infant born at 33 weeks gestation to a gestationally diabetic mother developed apnea and respiratory distress at 6 hours of age. Laboratory investigation demonstrated persistent hyperglycemia, and the patient was treated with continuous intravenous and subsequent subcutaneous insulin therapy. Detailed laboratory investigation to reveal the etiology of hyperglycemia and further endocrine evaluation were not significant. The baby's insulin requirement has continued thereafter, and she is being followed up in an outpatient clinic still under insulin therapy at 18 months of age. Neonatal diabetes mellitus should be considered in the differential diagnosis of neonatal hyperglycemia, and it may develop in newborns born to diabetic mothers, as well as neonatal hypoglycemia. Insulin treatment with close blood glucose monitoring is essential as long as hyperglycemia persists since neonatal diabetes mellitus may be either transient or permanent and it is not possible to differentiate these two outcomes before 18 months of age.