Normal and neoplastic epithelial cells produce growth factors that can affect cells from different lineages. Epithelial ovarian cancers produce M-CSF and IL-6. In the present study, production of these cytokines has been measured in the apparently normal epithelial cells from which epithelial ovarian neoplasms are thought to arise. Epithelial cells from the surface of premenopausal human ovaries were established in short-term cultures. The cells bound anti-cytokeratin antibodies and exhibited characteristic epithelial morphology by light and transmission electron microscopy. M-CSF and IL-6 were detected in supernatants from cultures of these cells, using assays specific for each factor. Cytokine levels were comparable to those in supernatants from ovarian and breast cancer cell lines. M-CSF expression could also be demonstrated by immunohistochemical analysis with specific rabbit heteroantiserum. Thus, M-CSF and IL-6 are produced constitutively by normal as well as by neoplastic ovarian epithelium.