AbstractThe definition of high‐risk multiple myeloma (HRMM) is evolving. Use of a clear definition of HRMM in clinical trials was not previously studied. We explored the definition of HRMM in completed phase III clinical trials. There is extreme variability in the definition and cutoffs used to define HRMM, with a significant number of studies lacking a clear definition. Our study provides a quantification of the variability in defining HRMM and suggests a need to better define HRMM in future clinical trials to enable more consistent treatment recommendations.