Hepatocyte growth factor (HGF) is known to take role in oncogenesis and tumoral behavior of the tumors of the organs that contain mesenchymal and epithelial cells together. This study aims to compare HGF levels in cyst fluids of epithelial ovarian cancer and benign ovarian cysts and look for the role of HGF in ovarian carcinogenesis. Twenty-four consecutive patients with ovarian cancer and 34 with benign cysts of ovary were recruited prospectively at Gynecologic Oncology Departments of SSK Ankara Maternity Hospital and Hacettepe University School of Medicine between 2001 and 2002. Cyst fluids were collected during primary staging in cancer patients and during laparatomy for benign patients. HGF levels were measured by enzyme-linked immunosorbent assay method. Median HGF levels of the benign ovarian cysts and epithelial ovarian tumoral fluids were found as 3822 pg/ml (85-15,253 pgr/ml) and 12,962 pgr/ml (4136-16,025 pgr/ml), respectively. Malign cyst fluids have higher HGF levels when compared with benign ovarian cysts (P < 0.01). This finding suggests that HGF may take a paracrine role in oncogenic differentiation and tumoral development of epithelial ovarian cancers. Mechanisms that take role in HGF secretion and the answers of the neighboring epithelial cells to HGF during tumoral development need to be investigated.