Infants’ arousals from sleep reflect the activation of various brain stem and cortical structures and their characteristics change with age. Arousal scoring based on the Pediatric Wake-up Club definition of arousal in infants was evaluated to determine whether arousals could be reliably identified and assessed in preterm infants also. Polygraphic recordings were made in seven stable preterm infants with a mean postconceptional age of 34.4±1.2 weeks. Fifty-two arousals were scored according to the guidelines of the Pediatric Wake-up Club (Consensus meeting in Brussels, 2002). Values of interest were assessed during the arousal period and during the 30-second periods before and after the arousal. The latter periods were subdivided into 10-second intervals and compared with the arousal period. The mean duration of arousal was 7±3 seconds. Respiratory rate was higher (35±15 bpm) during the arousal than in the periods preceding (29±14 bpm; p<0.01) and following (29±11 bpm; p<0.001) it. Heart rate decreased during the arousal (131±30 bpm) when compared with the preceding 10-second period (140±14 bpm; p<0.05). We found that arousals in preterm infants can be reliably identified and assessed using the Pediatric Wakeup Club’s arousal definition for term infants.