In the last two decades, there has been tremendous growth in two fields of study related to human infant development: (1) the development of neural processes during the early postnatal years and (2) the development of self-regulatory behavior. In an attempt to stimulate research on the relation between early brain development and self-regulatory processes, several hypotheses pertaining to the role of frontal lobe functioning in the development of emotion regulation during infancy are proposed. The results of a study of the relation between frontal electroencephalographic (EEG) activity and emotional behavior of 21-month-old infants are reported. It was found that increases in frontal lobe activation were associated with increases in emotional arousal, while EEG activity recorded from the parietal region showed either a reciprocal pattern of activation or did not change as a function of level of emotional arousal. These results provide evidence for the specialized role of the frontal lobe in mediating emotional behavior during infancy. © 1992.