|Preeclampsia is a multisystem disorder that complicates 3-8% of pregnancies and accounting 18% of maternal deaths. Classically, it is defined as hypertension and proteinuria with onset following the 20th week of pregnancy and associated with symptoms and signs such as edema, visual disturbances, headache and epigastric pain. In preeclamptic cases, no changes in serum sodium, potassium and calcium were found when compared with uncomplicated pregnancies. Total serum magnesium level was found to be significantly lower. As a rare complication of preeclampsia, hyponatremia has been described in fourteen cases. The prediction, prevention and management of hyponatremia in these cases require attention since this condition may predispose to convulsions, maternal mortality and fetal damage. Our case is a preeclamptic patient, presented with severe hyponatremia and convulsion. In this report, we discussed preeclampsia as a rare cause of severe hyponatremia that should be an indication for delivery. Also, the risk factors of preeclamptic hyponatremia were investigated, using a multifactorial approach for a further preventive strategy. Preeclampsia in twin pregnancies may be an independent risk factor for severe hyponatremia. Preeclampsia as a Rare Cause of Hyponatremia: Ilker Kahramanoglu, Merve Baktiroglu, Oguz Yucel and Fatma Ferda Verit.