Tissue engineering is rapidly growing now and can become a promising alternative to transplantation of organs and tissues,as it is devoid of major shortcomings of transplantology, such as acute shortage, complexity of selection, delivery andstorage of donor material, lifelong immunosuppressive therapy. One of the most widely known methods of obtainingbiological scaffolds for the subsequent creation of tissue-engineered constructs of organs and tissues is decellularization.The evaluation of the quality of the obtained scaffolds, based on the study of the viability of cell structures in decellularizedand recellularized matrices, is one of the priorities of modern regenerative medicine worldwide. In this investigation, thebiophysical criteria of decellularization and recellularization of tissue-engineered constructs based on the evaluation of thegeneration of free radicals in native, decellularized and recellularized tissues by EPR spectroscopy and chemoluminescencein a complex assessment of the quality of biological matrixes obtained are considered using intrathoracic organs and tissuesof rats. It has been established that the intensity indices of free radical generation in native and recellularized tissues ofanimal organs, as well as in decellularized matrices, can serve as one of the express criteria for quantitative assessment ofcell structures viability.