Choriocarcinoma is a malignant neoplasm with it's origin in trophoblast. It can be found after every pregnancy, but specially after pregnancy complicated by mola hydatidosa (complication in 2-3% of all molas). The main biochemical marker, used in treatment and prognosis is hCG. There are different prognostic systems for choriocarcinoma: presence of metastases, level of hCG in urine and plasma, end of last pregnancy. Surgical and chemical treatment in used. Outcome is generally good and very good.