Physiological and behavioral correlates of neonates in the supine and prone positions were examined. Polygrams were recorded in 10 newborn infants in the prone and supine positions. Newborn infants slept more in the prone position than in the supine, and quiet sleep was significantly more in the prone position. Gross movement, jerky movement and twitch movement were less in the prone than the supine position. There was no difference in localized movement or tremor-like movement in the two positions. Respiration was more regular in the prone than the supine position. Sleep apnea (greater than or equal to 6 seconds) was less in the prone position. The pulse rate during quiet sleep was higher in the prone position.