OBJECTIVE - To describe a case of severe DKA in an otherwise healthy pregnant woman. RESEARCH DESIGN AND METHODS - We describe 2.5 yr of close follow-up of a Bedouin woman who was hospitalized for DKA while pregnant with her 11th child. Plasma glucose returned to normal levels immediately after delivery of a dead conceptus. Four months later, while normoglycemic, the patient became pregnant again. During the subsequent pregnancy, GDM was diagnosed at week 20 of gestation. Tight plasma glucose control was achieved with an insulin regimen, and the patient delivered a healthy girl at term. Plasma glucose again returned to normal and remained so to date, 18 mo postpartum. An OGTT and a euglycemic hyperinsulinemic clamp were performed between pregnancies; another OGTT was performed at week 14 of the last pregnancy. Plasma glucose, insulin, and C-pepride were measured in blood samples during these procedures. RESULTS - We established beyond doubt that the patient developed GDM and returned to essentially normal glucose tolerance after her last (12th) delivery. During the 11th pregnancy, gestational diabetes was complicated by severe DKA. CONCLUSIONS - GDM is a common abnormality of glucose metabolism during pregnancy, which affects fetal development and leads to peripartum complications. Our report stresses that under certain circumstances, gestational diabetes can be complicated by DKA and become life-threatening to the mother and fetus.