The work function of dispenser cathode pellets has been determined by means of the retarding potential technique. A low‐energy electron gun was fabricated which delivers a collimated beam of electrons on the pellet surface at normal incidence. The set up is calibrated by employing samples of known work function such as gold and tungsten, prior to determining the work function of the cathode pellets. This set up provides a rapid determination of the work function of cathode pellets.