The purpose of this paper is to analyze the current state of developmental researches in the area of psychophysiology of emotions in preschool and elementary school children. Electrodermal and cardiovascular activity measures are considered as the sources of indices of the autonomic nervous system activation during emotion-eliciting stimulation in children. We discuss the question of sensitivity of phasic and tonic autonomic measures for the identification of occurrence of emotion, mapping it along with valence and arousal dimensions in affective space, and to further differentiate emotions by their physiological manifestations. Considered are the conceptual and methodological issues related to psychophysiological measurements and developmental factors affecting the emotional reactivity in children. Special attention is devoted to the developmental aspects of psychophysiological studies on emotion such as the maturation of organs, integration of the autonomic and central nervous systems, age and gender-related changes in autonomic reactivity, and development of inhibitory control. Summarized are main findings relevant to psychophysiology of emotions in preschool and early school-age children and suggested are most perspective directions of their integration in the framework of modern theories of emotion.