In premature infants, REM sleep. non-REM sleep and a short repeat of both, ultra dian rtythm, which normally develops in the fetus. in order. Care to enable normal systematic development, namely care to eliminate environment and factors that inhibit such development, is necessary. It is imperative for the maturation of proper circadian rhythm, the sleep-wake rhythm which develops after birth synchronously with environmental factors. that child care guidance utilizing rhythm entraining factors and other care is given to support the development of impeded sleep-wake rhythm of premature infants. Upon caring in the NICU. 1) assess the behavior state of the infant. avoid obstructing sleep, 2) cover the incubater upon of the head to block light. 3) adjust care intervention to the ultradian rhythm. 4) after 39 corrected weeks, move infant to recovery room with light-dark cycle. 5) if hospitalization exceeds 43 corrected weeks. extend the wake period by playing and by encouraging contact with the mother at a fixed daytime to establish a circadian rhythm. Child care guidance towards daily life after discharge that should be given are, 1) turning off all lights including dim lights during sleep at night, opening the curtains in the morning. 2) bathing before sleep at night, 3) one month after expected date of birth, sunbathing before noon. 4) after two months. parents leading an orderly life, 5) taking the infant for a walk or some exercise during the day and enjoying playing. 6) once the infant starts weaning (baby food), feeding regularly, 7) after five months. customarily sleeping and waking early.