The fundamental discovery and application by Kohler and Milstein of the procedure of lymphoid cell hybridization for the production of monoclonal antibodies brought a revolution in immunology and cell biology. With monoclonal antibody technology, it has become possible not only to solve or to be on the way towards solving a large number of fundamental biological questions, but a whole industry has been generated, the products of which are multiplying at tremendous speed. Monoclonal antibodies are an invention which led to the start of a new era in disease diagnosis. With their high specificity, purity and precise determination of epitopes, monoclonal antibodies provide a magnificent tool in immunodiagnosis. To harness everlasting benefits, monoclonal antibodies have been synthesized against H5N1 avian influenza virus with an intention of their possible use in diagnosis.