BACKGROUND AND AIMS: Poor sleep is associated with flares of inflammatory bowel disease (IBD). Studies often rely on subjective assessments of sleep and disease activity. Our aim is to use wearable devices to objectively assess the impact of inflammation and symptoms on sleep architecture in IBD. METHODS: Individuals >/=18 years old, diagnosed with and on medication for IBD, were enrolled in an observational study, answered daily disease activity surveys and wore a wearable device. Sleep architecture, sleep efficiency and total hours asleep were collected from the devices. Inflammatory markers were collected as standard of care. Associations between sleep metrics and periods of symptomatic and inflammatory flares and combinations of symptomatic and inflammatory activity were compared to periods of symptomatic and inflammatory remission. The rate of change in sleep metrics for 45 days before and after inflammatory and symptomatic flares were explored. RESULTS: 101 participants were enrolled contributing a mean duration of 228.16 (SD 154.24) nights of wearable data. Periods with active inflammation were associated with a significantly smaller percentage of sleep time in rapid eye movement (REM) and a greater percentage of sleep time in light sleep. Evaluating the intersection of inflammatory and symptomatic flares, altered sleep architecture was only evident when inflammation was present, and not with symptoms. Significant differences were observed in the rate that the percentage of time spent in deep and light sleep changed before and after inflammatory and symptomatic flares. CONCLUSIONS: Impaired sleep architecture is associated with inflammatory activity in IBD, and the presence of symptomatic flares alone does not impact sleep quality.