5 monoclonal antibodies have been produced by Köhler and Milstein. The production and the characteristics of the monoclonal antibodies are presented. They are all IgG1 and have high specificity against prostatic cells producing prostatic acid phosphatase. These monoclonal antibodies can be used to perform immunoscintigraphies and immunolymphoscintigraphies to titrate prostatic acid phosphatase serum levels and to identify the prostatic origin of a tumor.