The article investigates some processual aspects of digital textbook designing. Based on the analysis and generaliza-tion of theoretical research practice and methodological works in the field of pedagogical design, the stages of digital textbook designing from the standpoint of a system approach are determined, and their characteristics are given. Digital textbook designing is considered as a process that consists of stages, which in turn are divided into phases. A stage is interpreted as the most general part of the design, a process, which reflects the change in its states. The phase is interpreted as a part of the design process, which relates with creating a description of one or more design aspects or levels. Analytical, designing, experimental and reflexive stages were determined in the designing of the digital textbook. Such approach reflects the logic of design as a process, because the stages differ in their tasks, results and activities of subject of design. The analytical stage consists of diagnosis and goal setting phases, designing – conceptual, technological, operational, implementation phases, experimental – ascertaining, forming, control-generalizing phases, reflexive – adjustment and adaptation. Though, the conditional nature of the separation of these parts are emphasized in the article, because the real design process does not have a linear sequence in the passage of stages and phases, which are related in complex connections of interdependence and interpenetration.