Interruptions are common in busy clinical settings but carry patient safety concerns, particularly if they occur during medication administration. This retrospective cohort study examined one hospital’s timestamped telecommunications data to determine the effect of incoming mobile calls or texts on subsequent medication errors (based on barcode alerts) in a pediatric ICU. Medication administration errors were more common when nurses were interrupted by incoming telephone calls (3.7%) compared to when they were uninterrupted (3.1%), and error risk varied by shift, level of experience, nurse to patient ratio, and level of patient care required. Incoming text messages were not associated with medication administration errors; the authors speculate that this may be attributable to the fact that text message alerts do not require immediate response or that nurses have become accustomed to their frequent occurrence.