PURPOSE: The purpose of the work was to develop a practical electron cone and to compare its dosimetry with that of the conventional applicator collimation system. METHODS AND MATERIALS: The electron cone consists of the upper part of a manufacturer-supplied electron applicator and an institution-built rectangular extension tube which produces a 12 cm x 6 cm field at 100 cm SSD while maintaining an air gap of 5 cm between the patient. RESULTS: The compact size of the cone allows electron irradiation without having to reposition the patient after photon treatment. The radiation field is very similar to that of a standard 15 cm x 15 cm applicator with a 12 cm x 6 cm field restricting insert. Radiation leakage at the surface of the special cone is typically less than 1% of the useful beam at dmax. During 12 years of clinical use the special cone proved itself very practical in the treatment of more than 300 patients. CONCLUSION: An electron cone practical for clinical use with dosimetry comparable to the conventional applicator was developed.