Bispecific antibodies are able to redirect activated immunocompetent cells against simultaneously targeted tumor cells, which results in effective tumor cell lysis. After initial disappointing attempts, various novel concepts showed promising results for clinical effective therapy: the trifunctional antibody catumaxomab (EpCAM x CD3) was approved by the European Medical Agency to treat malignant ascites in patients with peritoneal carcinomatosis. BiTE (bispecific T-cell engager) molecules showed significant efficacy in phase II trials in patients with CD19-positive acute lymphatic leukemia. In this article, new developments in the field of bispecific molecules are evaluated from a clinical perspective.