The principles of thermostimulated inert gas release analysis (TIGRA), based on the measurements of inert gas migration in solids, are given. Methodological bases and the computer treatment of the TIGRA results are described. The potential and various applications of this method are demonstrated, e.g. the determination of inert gas mobility in metals, polymers, ionic crystals and ceramics, the characterization of non-crystalline solids and their changes.