The actual problem of interdisciplinary projects organizing is discussed. The purpose of the article is to justify the principles of planning and conducting the interdisciplinary medico-psychological research, in identifying its features in comparison with pseudo-interdisciplinary approaches. Types of interdisciplinary research are examined, distinctions are made between the true and pseudo-interdisciplinary approaches. The principles of true interdisciplinary research are formulated — the principle of choosing the object of study, the principle of determining the coordinates of the subject area of research, the hypothetico-deductive principle of interdisciplinary research and the principle of unity of interdisciplinary project methodology. The content of each principle is revealed by the example of medico-psychological research currently being carried out by the team of employees of the Institute of Psychology RAS and the National Medical Research Center of Traumatology and Orthopedics named after N.N. Priorov. It is shown that the system-structural approach to conducting the interdisciplinary medico-psychological research consists in coordinating theoretical constructs and empirical variables in accordance with the given coordinates of the research subject field and specific criteria for assessing the physical and mental state of the object of study. It is shown that the selected criteria allow, without leveling the specifics of individual scientific disciplines — medicine and psychology — to form a unified subject field of research and to develop an approach relevant for solving scientific and practical problems.