Published norms for infant sleep/wake patterns during the first 2 years of life include an increase in length of maximum sleep bout from four to five to eight to ten hours by 4 months but little decrease in total sleep in 24 hours from 13 to 15 hours. Thirty-two breast-fed infants were followed for 2 years and data collected on 24-hour patterns of nursing and sleep. Infants who were breast-fed into the second year did not develop sleep/wake patterns in conformance with the norms. Instead of having long unbroken night sleep, they continued to sleep in short bouts with frequent wakings. Their total sleep in 24 hours was less than that of weaned infants. This pattern was most pronounced in infants who both nursed and shared a bed with the mother, common practices in many nonwestern cultures. The sleep/wake development accepted as the physiologic norm may be attributable to the early weaning and separated sleeping practiced in western culture. As prolonged breast-feeding becomes more popular in our society, the norms of sleep/wake patterns in infancy will have to be revised.