Serous papillary ovarian cancer (SPC) is a highly aggressive tumor. About two-thirds of women have advanced disease at the time of diagnosis. Although many women with disseminated disease respond at first to combinations of surgery and chemotherapy, nearly 90% of tumors recur and women die of disease. Update progress in our knowledge of tumor-associated antigens and insight into mechanisms involved in immune-mediated recognition of these antigens, have provided a strong starting point for using the immune system as a model for novel therapy. In this study we determined the immunological profile of tumor-infiltrating lymphocytes (TILs), tumor-associated lymphocytes (TALs) in ascitic fluids, and lymphocytes from tumor draining regional lymph nodes (LNs) in SPC patients by CD20 (L26), CD8, and CD56 immunostaining. We examined 14 cases of TILs, 15 cases of TALs and 19 cases of LNs. TILs were infiltrating tumor stroma. No significant difference was detected in TILs, TALs and LNs in the expression of the B-cell marker CD20. In contrast, CD8 (T-cytotoxic) and CD56 (natural killer cell, NK) markers were dominant in LNs and TALs, but not in TILs. We conclude that SPC tumor lymphocytic infiltrate demonstrates a deplete T cytotoxic (CD8+) and NK cell (CD56+) immunophenotypic profile. This might in part explain the poor clinical outcome of the disease.