Background: Evidence of quality of life implications of asthma attacks are limited,particularly when measured on a utility scale, which enables calculating Quality-Adjusted Life-Years (QALYs) and comparisons with other health conditions andservices. Therefore, this study sought to estimate the utility loss associated with anasthma-related crisis event (accident and emergency (A&E) attendance or hospitaladmission).Methods: Participants were recruited in a cohort study from A&E and hospitaladmissions at three UK hospitals. They completed the EuroQol-5 Dimensions 5-Level(EQ-5D-5L), Asthma Quality of Life Questionnaire (AQLQ), Time trade-off (TTO), andpeak flow and symptom diary over 8 weeks, where three different methods (EQ-5D-5L,AQLQ, and TTO), were used to estimate utilities. The mean difference between twotime points were estimated using the Wilcoxon signed rank test.Results: From baseline to week 8, mean increases (95% CI) were estimated to be0.086 (0.019-0.153), 0.154 (0.112-0.196) and 0.132 (0.063-0.201) for EQ-5D-5L, AQL-5D (preference-based measure derived from AQLQ), and TTO respectively over 8weeks (p<0.01).Conclusion: Asthma crisis events are estimated to be associated with a mean utilityloss of between 0.086 and 0.132. The utility decrement can be used to assign valuesto asthma-related crisis events, which can enhance economic evaluations.