Forty two mothers who demonstrated an ability to identify standardized scents were tested as to their ability to recognize their own infant's smell. Positive recognition was defined as the ability to distinguish the infant's nonsoiled undershirt from two other infants' shirts. The undershirts were worn by the infants at least 13 hours prior to test period. Mothers were grouped by total time of previous exposure to their infants. All infants were healthy full term infants born after uncomplicated pregnancies and deliveries.In Group 1(n=10) with exposure of less than 10 minutes, successful recognition occurred in 20%; Group 2(n=10), exposure 10-60 minutes, success was 90%; Group 3(n=22), exposure over 1 hour, success was 100%. There was no effect of maternal analgesia or anesthesia on recognition rate.We thus conclude that the newborn's body odors are important cues for maternal identification of their babies in the immediate newborn period.