Cytocentrifuged cell preparations have been evaluated as substrates for the demonstration by immunofluoresence of T cell surface antigens. Results obtained by a 2-stage method with fluorescent conjugate specific for the isotope of the first stage monoclonal antibody, and by a 3-stage procedure employing an intermediate antiserum to mouse IgG as amplifying agent, showed good correlation with those obtained by a standard technique performed on cells in suspension. These methods have the advantages of requiring fewer cells and less antibody and the cytocentrifuge preparations may be stored for batch assay.