Peritoneal carcinomatosis remains an unsolved medical problem in modern oncologic treatment. Excruciating symptoms such as malignant ascites, ileus, nausea, vomiting, dyspnoea and pain deteriorate the quality of life for affected patients. There is still no effective standard treatment for peritoneal carcinomatosis. The trifunctional antibody catumaxomab (antiepithelial cell adhesion molecule x anti-CD3) is able to direct T lymphocytes and Fcg-receptor-positive accessory cells to epithelial cell adhesion molecule-positive tumor cells. Intraperitoneal catumaxomab therapy was shown to be the first effective therapy against accumulation of malignant ascites in patients with peritoneal carcinomatosis of epithelial cancer, reducing the need of paracentesis and prolonging puncture-free survival. This paper reviews the mode of action of catumaxomab and analyzes different fields of local immunotherapy in patients with peritoneal carcinomatosis. A summary of completed and ongoing studies is included. Catumaxomab is discussed to be an outstanding option for local control and therapy of peritoneal carcinomatosis, which could be an optimal modular therapy in addition to systemic chemotherapy and surgical tumor resection.