Objectives: To determine critical care nurses' knowledge of alarm fatigue and practices toward alarms in critical care settings.Research methodology/design: A cross-sectional survey using an adaptation of The Health Technology Foundation Clinical Alarms Survey.Setting: A sample of critical care nurses (n = 250) from 10 departments across six hospitals in Ireland.Results: A response rate of 66% (n = 166) was achieved. All hospital sites reported patient adverse events related to clinical alarms. The majority of nurses (52%, n = 86) did not know or were unsure, how to prevent alarm fatigue. Most nurses (90%, n = 148) agreed that non-actionable alarms occurred frequently, disrupted patient care (91%, n = 145) and reduced trust in alarms prompting nurses to sometimes disable alarms (81%, n= 132). Nurses claiming to know how to prevent alarm fatigue stated they customised patient alarm parameters frequently (p = 0.037). Frequent false alarms causing reduced attention or response to alarms ranked the number one obstacle to effective alarm management; this was followed by inadequate staff to respond to alarms. Only 31% (n = 50) believed that alarm management policies and procedures were used effectively.Conclusion: Alarm fatigue has the potential for serious consequences for patient safety and answering numerous alarms drains nursing resources. (C) 2018 Elsevier Ltd. All rights reserved.