Diabetic ketoacidosis (DKA) is a serious complication of diabetes resulting often in a medical emergency. Nowadays, the occurrence of DKA is rare in pregnant women with diabetes, occurring mainly in patients with type 1 diabetes, but also in type 2 or, more rarely, in women with gestational diabetes mellitus (GDM). Maternal and fetal complications determined by DKA can be life threatening, so prompt recognition and treatment of this condition is mandatory to avoid these complications.