Abstract Background Severe illness in children is associated with significant risk of permanent disability, cardiac arrest, and death. The Severe Illness Getting Noticed Sooner (SIGNS) for Kids was created by an expert panel to help parents and other caregivers identify and articulate signs of severe illness to enable timely escalation of care. SIGNS for Kids consists of 5 major items: Behaviour, Breathing, Skin, Fluids, and Response to usually effective treatments. Expert development ensured face validity, however there is no formal validity evidence to suggest the tool can identify children with severe illness. Objectives To provide preliminary validity evidence of the sensitivity of the SIGNS criteria as markers of severe illness. Design/Methods A retrospective review of paediatric deaths was performed using records from the coroner’s office. Eligible patients had an index event described and were <18 years and >36 weeks gestational age at the time of event, had observations/reports for > 6 hours prior to the index event, and were not in an intensive care unit (ICU) or under anaesthetist supervision. The index events were defined as cardiac arrest, respiratory arrest, intubation, transfer to ICU, interfacility transfer, or urgent surgical procedure. Traumatic events and infants with sudden unexplained death were excluded from analysis. The main outcome was the presence of SIGNS items. Secondary measures were the time before index events that each of the SIGNS were present, and the time to death from the index event. Analyses were descriptive. Results Two hundred records were screened. After exclusion of 145 cases with incomplete records or traumatic deaths and 5 infants with sudden unexplained death, the records of 50 children met inclusion criteria. One or more SIGNS criteria were present before index event in 48 (96%). Breathing abnormality n=26 (52%) was the most frequently observed item with a mean (SD) duration of 47 (51) hours prior to index event. Over half (n=28, 56%) had SIGNS documented for ≥24 hours before initial escalation and 42 (84%) died within 48 hours after index event. Conclusion Forty-eight of 50 children had SIGNS criteria present before index event, and half had SIGNS present >24 hours. These data provide evidence of the sensitivity of the SIGNS criteria as markers of severe illness. Future studies will focus on establishing specificity and construct validity as well as caregiver usability prior to implementation of the screening tool.