Multiple myeloma is a malignant plasma cell disease, which typically affects older patients, with a median age at diagnosis of 70 years. The challenge in treating older patients is to accurately identify ‘fit’ patients that can tolerate more intensive treatment to maximize disease control, while simultaneously identifying vulnerable or ‘frail’ patients who may develop toxicity with significant morbidity and mortality, requiring different treatment options or dose modification. Multiple frailty scores have been devised for multiple myeloma over the years in newly-diagnosed patients. This paper gives an overview of the three common frailty measurements: the International Myeloma Working Group Frailty Score, Mayo Clinic Frailty Score and the Revised Myeloma Co-Morbidity Index. We will summarize the derivation, validation, usability and applicability of these scores in different clinical settings, emphasizing the main strengths and limitations for each index score. We will also highlight future directions in the operationalization of frailty in multiple myeloma.