[en] The use of non-ionizing radiation (NIR) sources in the scientific, medical, industrial and domestic areas is becoming increasingly widespread. Concern has been expressed of the increased possibility of exposure of employees and of the public to NIR. Regulatory authorities have the role of ensuring that all organisations using NIR source keep the exposure of all persons below prescribed limits. The lecture notes draw together the basic information on NIR protection including essential quantities and units, biological interactions, protection standards, measurement techniques and personnel protection