AbstractA device commonly used for cell electrophoresis is the cytopherometer. Its application in an immunological tumor test, however, pointed out many shortcomings and instabilities. In order to use cytopherometers in cellular immunology, a procedure was worked out to stabilize this instrument. By enlarging the electrode chambers, using a simple and efficient buffer in all compartments, coating the electrophoresis chamber, and by following a set of electrophoretic parameters (current, temperature,etc.), an intraassay variance of 1.8 % and an interassay variance of approximately 1 % were reached.