Objectives: Bedtime procrastination is defined as going to bed later than intended, without having external reasons for doing so. According to previous studies, bedtime procrastination is strongly associated to usage of smart devices before bedtime. However, there is a lack of in-depth research about the function of smartphone usage before bedtime, and which applications are used frequently in association with bedtime procrastination. Therefore, the current study, preliminary research, investigates the usage patterns of smartphone applications of individuals with high levels of bedtime procrastination. Methods: Participants consisted of 20 adults (female=80%, age=20.9±2.05 years) who scored higher than 33 on the Bedtime Procrastination Scale. All participants completed a 7-day sleep diary, Insomnia Severity Index, and the Center for Epidemiological Studies Depression Scale. On the sleep diary, participants were asked to track the specific type of smartphone application they used and time they engaged in the specific application prior to bedtime. Results: Among the different main categories, bedtime procrastinators spent significantly more time on communication and leisure prior to bedtime. In addition, the correlation between depression and amount of time spent watching movie/television/video, and between insomnia severity and time spent communicating through cellphone messenger service were significant. Conclusions The results of this study provide insight into which smartphone applications bedtime procrastinators spend the most time prior to bedtime. The results suggest that the main functions of using their cell phone prior to bedtime are for entertainment and social interaction.