Radiotherapy is an often used treatment in glomus tumors of the middle ear. Histologic evidence revealing nonuniform radiotherapeutic effect on tumor vessels is shown. The reticular tumor stroma is replaced by collagen. The chief cells demonstrate little change. The results in 19 radiated patients demonstrate that radiation eliminated the tumor in 20% of the cases. Radiation followed by surgery was more successful in tumor eradication than surgery followed by radiation.