Objective:To determine risk factors for mechanical (noninfectious) complications in peripherally inserted central catheters (PICCs) in children.Design:Retrospective cohort study.Setting:Pediatric tertiary-care center in Nova Scotia, Canada.Patients:Pediatric patients with a first PICC insertion.Methods:All PICCs inserted between January 2001 until 2016 were included. Age-stratified (neonates vs non-neonates) Fine–Grey competing risk proportional hazard models were used to model the association between each putative risk factor and the time to mechanical complication or removal of the PICC for reasons not related to a mechanical complication. Models were adjusted for confounding variables identified through directed acyclic graphs.Results:Of 3,205 patients with PICCs, 706 had mechanical complications (22% or 14 events/1000 device days). For both neonates and older children, disease group, lumen count, and prior leak were all associated with mechanical complications in the adjusted proportional hazards model. Access vein and prior infection were also associated with mechanical complications for neonates, and age group was associated with mechanical complications among non-neonates.Conclusions:We have identified several risk factors for mechanical complications in patients with PICCs that will help improve best practices for PICC insertion and care.