Renal failure occurring in pregnancy or post partum is an unusual but well-described complication. Acute renal failure seems to be associated more often with HELLP syndrome rather than with pre-eclampsia or chronic hypertension. Probable overlapping of HELLP and hemolytic uremic syndrome in pregnancy or postpartum should be taken into consideration when treating pregnant women who show signs of proteinuria, hypertension, hematuria, increase of reticulocytes, decrease of haptoglobin with thrombocytopenia and microangiopathic hemolytic anemia. Our case refers to a 32 year old woman at 32 weeks gestation in twin pregnancy who presented with HELLP syndrome and renal failure. Immediately postpartum oliguria was noted and the laboratory analyses suggested the coexistence of HELLP and hemolytic uremic syndrome. In patients with gestosis and/or HELLP syndrome presenting oliguria combined with a decrease of hemoglobin level not due to intraoperative hematic leaks it is always necessary to ask for haptoglobin dosage. In treating hemolytic uremic syndrome it is very important to use a high dosage of plasma and sometimes plasmapheresis. HELLP syndrome contributes to various complications which are sometimes responsible for kidney or maternal mortality. In treating these patients early diagnosis combined with a specific treatment can considerably reduce kidney and maternal mortality.