In comparison with the first half of this century the frequency of X-ray induced lesions diminished spectacularly both in patients and in radiologists in the second half; this was due to more and more rigorous radioprotection. The present measures of radioprotection may be divided into two groups according to their appliance to the patient or the operator. Prevention of irradiation of an unknown pregnancy is the responsibility of the clinician (application of the 10 days rule) but equally of the radiologist (warning poster in the radiological department, query of possible pregnancy). The sensitivity of the imaging material has been raised by adaptation of film, intensifying screens, grids and the use of image intensifier with TV-chain and photofluorography. The quantity of X-rays to the patient may be directly lowered by reducing the time and dose of fluoroscopy, the number of radiographs, by using a diaphragm, by covering some organs with lead shields and by choosing different examination modalities. Dose reduction to the patient may also be achieved by modifications of the quality of the X-ray beam (filter, KV/MA) and by proper indication of the examination. Patient's dose can be calculated by phantom simulation and by chromosomal blood study. The operator is never allowed to put his unprotected hand in the X-ray beam. The amount of scattering radiation to the operator will be lowered by several of the above mentioned measures reducing the patient's dose and by choosing the most favourable direction of the axis X-ray tube-image intensifier. Direct protection of the operator is achieved by lead-glass screens, lead flaps around the patient, lead gloves, apron and glasses and by raising the distance between the operator and the X-ray tube. Early detection of unusual radiation is possible by systematic dosimetry.