A review of literature on the possibility of regeneration of muscle fibers under the artificial myocardium trauma in frogs, newts, lizards, newborn kittens, rats and guinea pigs, in very small foci of trauma in adult dogs and rabbits, under the stimulation of regeneration in adult rats, rabbits and dogs. The data are given about growth and secondary differentiation of muscle fibers in the myocardium of chick, mammal and human embryos, as well as of adult cocks and rabbits under the definite conditions of explantation. It was noted that the sources and mechanism of formation of muscle fibers remained as yet unclear, as well as the causes preventing the myocardium regeneration in adult mammals under routine conditions of traumatization. It is stressed that the problem of myocardium regeneration is as yet not solved and, being one of the most important biological problems, needs further studies.