The problem of development of lateralization of motor systems in the course of early ontogenesis is important for understanding regularities of formation of functional characteristics of motor control. To solve these tasks, in the 8-74-day old rat pups the presence of lateralization was studied in two motor tests: the choice of the preferable rotation direction at holding the rat by the tail and the choice of one of the forelimbs in the test of initiation of the limb placement onto a support. It has been shown that in early ontogenesis, until the age of the sexual maturation, no constant lateralization is observed in realization of the unconditional motor reactions in any of the performed tests. The turning point of the establishment of the lateral preference has been revealed to correspond to the three-week age (the 21-23rd days), while the final lateralization both for individual animals and for the entire sample takes place at the age of 1.5-2 months. It is suggested that development of lateralization of the limb placement on a support occurs with the approximately two-week delay as compared with the process of formation of the preference in the choice of the rotation direction.