The HELLP syndrome is a severe and life-threatening complication of preeclampsia with typical laboratory findings. The frequency of the disease is 1 to 150-300 live births in perinatal centers. The median gestational age at presentation is 34 weeks, however, the disease may also develop during the early postpartum period. Right upper quadrant pain is the most striking clinical symptom; in up to 15% of cases neither hypertension nor proteinuria is present on admission. For the detection of hemolysis determination of haptoglobin levels is the most suitable method. Coagulation disorders are more pronounced in patients with the HELLP syndrome as compared to those with preeclampsia without the HELLP constellation, however the full-blown syndrome of disseminated intravascular coagulation (DIC) is not a leading symptom but the consequence of delayed diagnosis and/or therapy of the primary disease. The course of the HELLP syndrome is unpredictable. On the one hand, complete reversal of symptoms under conservative treatment have been reported in individual cases, on the other hand, rapid, therapy-resistant deterioration of the disease had been observed in the majority of patients accompanied by severe complications (e.g. liver rupture). As a consequence the mother and the newborn need intensive care, and these women should be delivered in an obstetric intensive care unit. The maternal mortality reported from the international literature is 3.3%, and the perinatal mortality 22.6%.(ABSTRACT TRUNCATED AT 250 WORDS)