Objectives: To determine the incidence of tracheostomy accidental decannulations (AD) among pediatric inpatients and identify risks for these events.Study Design: Prospective cohort. Methods: All tracheostomy patients (≤18 years) admitted at a tertiary children's hospital between August 2018 and April 2021 were included. AD were recorded and patient harm was classified as no harm/minor, moderate, or severe. Monthly AD incidence was described as events per 1000 tracheostomy-days.Results: One-hundred seventeen AD occurred among 67 children with 33% (22/67) experiencing multiple events (median: 2.5 events, range: 2-10). Mean age at AD was 4.7 years (SD: 4.4). AD resulted from patient movement (32%, 37/117), performing tracheostomy care (27%, 31/117), repositioning or transporting (15%, 17/117), or unclear reasons (27%, 32/117). A parent or guardian was involved in 28% (33/117) of events. Nearly all AD resulted in no more than minor harm (84%, 98/117) but moderate (12%, 14/117) and severe (4%, 5/117) events did occur. There were no deaths. Tracheostomy care or repositioning were frequently responsible in acute versus subacute events (48% vs. 26%, p = 0.04). Mean monthly AD incidence was 4.7 events per 1000 tracheostomy-days (95% CI: 3.7-5.8) and after implementation of safety initiatives, the mean rate decreased from 5.9 events (95% CI: 4.2-7.7) to 3.7 events (95% CI: 2.5-5.0) per 1000 tracheostomy-days (p = 0.04).Conclusions: AD in children occur at nearly 5 events per 1000 tracheostomy-days and often result in minimal harm. Quality initiatives targeting patient movement, provider education, and tracheostomy care might reduce the frequency of these complications.