Abstract: New diagnostic methods are being sought for ovarian cancer due to its higher prevalence, which is the result of an increase in the share of elderly women. The purpose of this study was to analyze the content and sensitivity of immunoglobulins and the phagocytic activity of peripheral blood in order to improve the diagnostics of ovarian cancer among elderly women. The phagocytic activity and the immunoglobulin level in the peripheral blood were assessed with immunological and spectrophotometric methods in 78 patients with ovarian cancer aged 65–70 years. The control group comprised 42 women of the same age with no ovarian cancer. The primary importance of circulating immune complexes and the indices of neutrophil activity and the inhibition of phagocyte migration was established for laboratory diagnostics of ovarian cancer among elderly people. The use of highly informative parameters of systemic immunity may enhance the diagnostics of ovarian cancer in the elderly. © 2020, Pleiades Publishing, Ltd.