Ovarian cancer is the most aggressive gynecological cancer and is often diagnosed in advanced stage. Constantly we are looking for new prognostic factors which would enable early diagnosis, increase the effectiveness of therapeutic intervention. There is to little data about immunological predictors in ovarian cancer. The tumor's microenvironment is designated by regulatory T cells, cytotoxic T cells, dendritic cells (DCs), tumor - associated macrophages (TAMs), monocytes, plasma cells and cytokines, such as IL-6, IL-8, IL-10, IL-17 and TGF-beta. Some of them are responsible for the inhibition and others induce tumor growth. Ovarian cancer patients with high ratio of CD8 + TILs to Treg present longer overall survival time (OS). The presence of T helper cells in ascites is associated with longer OS. Furthermore, patients with a lower rate plasmocytoid DCs infiltrating tumor tissue demonstrate longer progression-free survival time (PFS). Women with increased M1/M2 ratio present higher five-year survival rate. The presence of immunologically competent cells and secreted cytokines give motivation to evaluate their prognostic value. Perhaps this strategy will contribute to longer progression-free survival time and overall survival time in those patients.