Purpose: Cell-free and concentrated ascites reinfusion therapy (CART) is intended to treat patients by ultrafiltration and reinfusion of their refractory ascites. In the CART system, bacteria and cancer cells in removed massive ascites are filtrated. Then, water is removed in the condenser, resulting in a higher protein concentration. The purpose of this study was to assess the clinical usefulness of CART in the treatment of refractory massive ascites in patients with cancerous peritonitis. Materials and Methods: CART was performed 13 times in four patients with ovarian and endometrial cancer. Results: Autologous protein with a higher concentration was intravenously administered. The amount of aspirated and condensed ascites was 3,190 ± 1,086 ml (975 4,500 ml) and 538 ± 249 ml (100 - 860 ml), respectively. Condensed albumin, albumin concentration, and concentration time were 43.2 ± 25.8 g, 8.2 ± 3.3 g/dl, and 73.3 ± 24.8 min (28 - 122 min), respectively. CART was effective in maintaining serum albumin concentrations, and it is possible to repeat infusion. During CART, patients performance status was 1-2 and vital signs were stable except for mild elevations in body temperature. Daily life was maintained without serious side-effects. Conclusions: The use of CART for gynecological cancer patients with refractory massive ascites due to cancerous peritonitis contributes to improvements in quality of life and relief of symptoms. With autologous infusion of condensed ascites, patients can avoid infection, allergic reactions, and administration of expensive blood products.