Despite the fact that digital technologies are more and more used in the learning and education process, there is still lack of professional evaluation tools capable of assessing the quality of used digital teaching aids in a comprehensive and objective manner. Construction of the Comprehensive Evaluation of Electronic Learning Tools and Educational Software (CEELTES) tool was preceded by several surveys and knowledge obtained in the course of creation of digital learning and teaching aids and implementation thereof in the teaching process. The evaluation tool as such consists of sets (catalogues) of criteria divided into four separately assessed areas - the area of technical, technological and user attributes; the area of criteria evaluating the content, operation, information structuring and processing; the area of criteria evaluating the information processing in terms of learning, recognition, and education needs; and, finally, the area of criteria evaluating the psychological and pedagogical aspects of a digital product. The specified areas are assessed independently, separately, by a specialist in the given science discipline. The final evaluation of the assessed digital product objectifies (quantifies) the overall rate of appropriateness of inclusion of a particular digital teaching aid in the teaching process.