Serum concentrations of hepatocyte growth factor (HGF) were measured in 60 patients suffering from acute myelocytic leukaemia (AML). At the time of diagnosis elevated HGF concentrations (> 1.25 ng/ml) were found in 28% of the patients. HGF levels correlated with the presence of disseminated intravascular coagulation (DIC), levels of lysozyme, creatinine, peripheral blood blast counts and lactic dehydrogenase. In the group of patients with high HGF (>1.25 ng/ml) we found a tendency towards an increased early mortality; 41% of them died within 15 d from diagnosis, as opposed to 5% of the patients with normal HGF (log rank test p=0.07). DIC-related bleeding or thrombosis contributed to this early mortality. In responders, HGF levels normalized after treatment. HGF levels are low in neutropenia and neutropenic infections.