The problem of general regularities of abnormal development are analyzed from the standpoint of cultural-historical psychology. The importance of its solution is substantiated not only for the problems of differential diagnostics of a child abnormal development, but also for designing the practice of psychological assistance in accordance with its individual characteristics. An interpretation of the regularities of abnormal development as violations, lags or distortions of the work of the regularities of normal mental development is proposed. The regularities of abnormal mental development can be divided into two groups: the first reflects deviations in the formation of higher mental functions, the second — deviations in the work of general development regularities that reveal the dynamics of changes and the systemic interaction of mental functions.