Bispecific monoclonal antibodies (BiMAb) have been shown to be able to contribute to an immunological approach in cancer therapy. In this review, essential aspects regarding the production of BiMAb and modes to apply them in immunotherapy for cancer are discussed. The pros and cons of BiMAb are considered, and the development from application in animal models to clinical studies is reviewed. The most important clinical trials are summarized, and the different problems encountered are discussed. Provided some crucial problems can be overcome, BiMAb will have a place in the treatment of cancer, especially in the setting of minimal residual disease.