The present study uses the glabellar reflex and reflex modification procedures to assess acoustic and tactile sensory processing capabilities in the human neonate. Fourteen term infants and 28 clinically stable preterm infants were given identical test paradigms. Augmentation testing consisted of a 16 V dc tap presented simultaneously with a 90 dB SPL tone; inhibition testing consisted of a 16 V tap preceded 900 msec. by an identical tap. All 14 term infants showed augmentation with 8 of 14 at p less than 0.05 level and eleven of 14 showed significant inhibition at the 900 msec intertap interval. However, only 12 of 28 preterm infants demonstrated significant augmentation and none showed reliable inhibition. These data indicate that areas of the central nervous system that process sensory stimuli are not fully developed at the time of birth even in the term infant. Further, the neural system for augmentation and inhibition may be independent of each other.