The article deals with the advantages and diagnostic possibilites of the nondestructive method of infrared reflectography, a useful tool for the physicochemical study of Byzantine icons. The principle of the method, with some reference to the visual behavior of the pigment layers as regards the infrared radiation, and the equipment used for its application are also described. The application of this method to four especially chosen Byzantine icons dating from the 9th to the 18th centuries of the Byzantine Museum in Athens, Greece, showed the existence of damages and overpaintings as well as the artist's initial drawing on the ground preparation; it also led to an approximate identification of the pigments used in the successive layers of the painting. -- AATA