In a prospective analysis the effectiveness of roentgen irradiation with minimal doses (daily single doses .03 Gy up to a total dose of 1.5 Gy) was investigated in 207 patients with an epicondylitis humeri. Compared with a group of 92 patients, who were irradiated with higher doses being in general use (weekly 2x single doses 1.0 Gy to a total dose of 4.0 Gy), the therapeutic results show no significant differences. After termination of the first irradiation series an improvement of complaints was seen in half of the patients (48.8% or 50.0%). A further increase of the quota in success to 74.9% or 70.6% was found 6 weeks after termination of irradiation. By reason of radiotherapeutic results, mainly attained in chronic states of epicondylitis humeri after primary conservative therapy without success for months and partly surgical pretreatment, the radiotherapy should be used more frequently than till now, especially in consideration of its slight side-effects and injuries of patients.