The use of x-rays in radiation therapy, particularly when benign conditions are treated, has created an interest in the gonadal dose delivered during such procedures. The study to be described here was initiated to investigate the gonadal dose as a function of x-ray energy, field size on the skin, and patient size, for various irradiated sites. The initial phases of this investigation have been carried out mainly in male patients. The study will be extended to include females and children. The exposure dose was recorded with Victoreen 10-mr stray radiation chambers and Baldwin-Farmer type B.D. — 2/15 ionization chambers. For males, the chambers were taped to the scrotum, while in females the chambers were inserted in the vagina against the face of the cervix. Difficulties encountered were the very great energy dependence and directional dependence of some of the ionization chambers used. Chambers will be developed to extend the range of the present measurements to lower qualities common in dermatological practice. All chambers were calibrated against a secondary standard previously calibrated by the National Bureau of Standards. The results to be presented at this time include irradiations to the head, neck, and shoulder areas for malignant lesions. These radiation fields are analogous to those used in dermatological practice, bursitis, chronic tonsillitis, keloids, inflammatory thyroid disease, etc. (1). Other areas will be investigated in future work. All dosages given are those recorded during actual treatments and with the use of coned fields. Observations on 34 cases are summarized in the accompanying table.