This paper examines the analytical power of fluorescence activated cell sorting and immunorosetting technique as compared with the newly devised microplate selection technique in identifying transfected murine L cells expressing human surface molecules. The microplate selection technique relies on the mechanical transfer of transfected cells to a terasaki microplate, where an indirect immunofluorescence assay is carried out. It is a simple procedure not requiring costly equipment and with a detection capacity equivalent to that of the fluorescence activated cell sorter. The microplate selection technique proved to be sensitive enough to detect all the transfectants produced during the present study.