In this prospective, descriptive study, we used a repeatedmeasures design to explore the 24-hour effects of caregiving and positioning on preterm infants' states and the factors associated with state changes. Thirty preterm infants (gestational age 27.6-36.1 weeks) were observed for 3 days in the neonatal intensive care unit to record six states: quiet sleep (QS), active sleep, transition, active awake, quiet awake, and fussy or crying. The occurrences of QS increased when infants received no caregiving, social interaction, non-nutritive sucking (NNS), and were laterally positioned. However, QS significantly decreased and fussy or crying state increased when infants received routine and intrusive caregiving. These results suggest that caregiving, NNS, and positioning should be appropriately provided to facilitate infants' sleep, and reduce fussiness or crying. ß