Introduction Esports is becoming increasingly professionalized, yet research on performance management is remarkably lacking. The present study aimed to investigate sleep and mood in professional esports athletes. Methods Participants were 17 professional esports athletes from South Korea (8), Australia (4) and the US (5) who played First Person Shooter games (mean age 20±3.5 years, 100% male). All participants wore a wrist-activity monitor for 7–14 days, and completed subjective sleep and mood questionnaires. Results Based on data from the wrist-activity monitory, participants averaged 409±37 minutes of total sleep time, and 87±1% of sleep efficiency per night. All participants had significantly delayed sleep patterns (Average bed Time 3:41 am and wake Time 11:11 am). Participants had an average SOL of 26.15 minutes and prolonged wake after sleep onset of 51.91 (±31.84) minutes. Korean players had significantly higher depression scores compared to the other groups (p=.006) and trained longer than the Australian or US teams (13.38 vs. 4.75 vs. 6.10 hours, respectively). Depression scores were strongly correlated with number of awakenings, wake after sleep onset and training time per day (ps<.05). Conclusion As the first exploratory study in the esports field, the study indicates that esports athletes show delayed sleep patterns and have prolonged wake after sleep onset. These sleep patterns may be associated with mood (depression) and training time. There may also be cultural differences that contribute to sleep disturbance in this population. Support Korean Society of Sleep Medicine