Peritoneal cavity is the primary site of ovarian cancer metastases. It is believed that the intraperitoneal invasiveness of the malignancy is determined by interactions between cancer cells and the normal peritoneal mesothelum. The nature of these interactions is, however unclear which is the reason for divergent opinions about the role of mesothelial cells in disease progression. According to some authors, the mesothelium acts as a barrier which prevents the expansion of the tumor cells. However other researchers claim that these cells actively promote various elements of cancer cell invasiveness. The aim of this study was to present both concepts of the role of the mesothelial cells in the intraperitoneal development of ovarian cancer metastases, with particular emphasis on the mechanisms of reciprocal interaction between normal and cancer cells.