Objectives: Disturbed and/or shortened sleep is reported by individuals engaged in on-call working arrangements, as a result of either overnight calls or stress. Given the known adverse impact of sleep disruption on cognitive performance, and the safety- and time-critical nature of on-call work, changes to sleep in on-call workers may have significant impacts. As such, this laboratory study aimed to investigate the impact of being on-call on sleep over consecutive nights. It was expected that additional nights on-call would result in more disturbed sleep.