The treatment of hemangiomas with X-rays has been sharply criticized because of their tendency to involute spontaneously. It has been the aim of this catamnestic study to re-examine for X-ray injury those patients, whose hemangiomas were irradiated 15–20 years ago. The findings indicate that signs of roentgenoderma can appear already with 800 r and increase rapidly over 1,500 r. The observed irreversible damages, however, were mostly not grave, but admonish a certain amount of restraint. An assessment of the effectiveness of low X-ray doses still requires verification considering a faster spontaneous involutio