Healthy infants' sucking, swallowing and breathing movements were observed ultrasonographically during breast- and bottle-feeding between two and five days after birth. Sucks were found to occur either on their own or in combination with a swallow. Swallows did not occur on their own. Younger babies' swallowing invariably was associated with a pause in breathing. Older babies generally showed better co-ordination of sucking, swallowing and breathing than younger ones, whether breast- or bottle-feeding.