The dictionnary of radiation protection terms has been compiled by CMEA member-country specialists under the auspisious of Scientific-Technical Council for Radiation Protection of the Permanent Commision for Peaceful Atomic Energy Applications as a means for better mutual understanding in collaborative activities. The dictionnary incorporates, along with Russian terms, the corresponding ones in the official languages of CMEA member-countries who participated in its compiling: Bulgarian, Hungarian, German, Spanish, Polish, Roumanian, Czech as well as English. The dictionnary consists of three sections: 1) Ionizing radiation; 2) Ionizing radiation interaction with materials. Ionizing radiation dosimetry; 3) Radiation protection. The first section contains 16 terms, the second - 25, the third - 110. The terms within the section are arranged in sense sequences.