Hepatocyte growth factor (HGF) is known to take a role in oncogenesis and tumoral behavior of the tumors of the organs that contain both mesenchymal and epithelial cells. This study compares HGF levels in cyst fluids of epithelial ovarian cancer and benign ovarian cysts to look for the role of HGF in ovarian carcinogenesis. Twenty-four consecutive patients with ovarian cancer and 34 with benign ovarian cysts were recruited prospectively at the 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 ELISA method. Median HGF levels of the benign ovarian cysts and epithelial ovarian tumoral fluids were found to be 3822 pg/ml (85-15,253 pg/ml) and 12,962 pg/ml (4136-16,025 pg/ml), respectively. Malignant 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 a role in HGF secretion and the responses of neighboring epithelial cells to HGF during tumoral development need to be investigated.