The work was designed to reveal the effect of maternal deprivation on the behavioral reactions of rat pups during the intermittent and prolonged maternal separation. Research was conducted on 126 white rat pups of both sexes received from 26 mothers at the 1st, 15th, 21st, and 60th days after birth. All animals were divided into three main groups: the first group included 42 litters submitted to intermittent maternal deprivation (IMD). The second group included 28 litters submitted to prolonged maternal deprivation (PMD) and 56 litters served as the control group. Animals were housed in a room with a controlled temperature, humidity, 12 h light/dark cycle, having free access to the food and water. The received results testify to essential influence of maternal deprivation on the normal functioning of CNS, revealed in the alterations of behaviors in rats suffering from maternal deprivation. Thus, early maternal separation in rat pups may serve to be the stressful stimulus for CNS and alter it function, which produces the behavioural disorders among them.