ObjectiveTo evaluate the psychometric properties of the AL‐PROfile, a patient‐reported outcome measure combining the Patient‐Reported Outcomes Measurement Information System (PROMIS)‐29, two items from PROMIS Cognitive Function, and select Patient‐Reported Outcomes version of the Common Terminology Criteria for Adverse Events (PRO‐CTCAE) items.MethodsContent validity was assessed through cognitive debriefing interviews of 20 patients who completed the AL‐PROfile (Study 1). Study 2 involved 297 participants who completed the AL‐PROfile and Medical Outcomes Study 36‐item Short‐Form Health Survey (SF‐36). Reliability (internal consistency and test–retest reliability) and validity (convergent and discriminant validity, known groups validity by stage/organ involvement) were calculated.ResultsStudy 1 participants found the AL‐PROfile straightforward confirming the relevance of the included content. Some felt that certain questions were not related to their amyloidosis experience. Study 2 demonstrated acceptable internal consistency for all domains/items except PROMIS Cognitive Function and acceptable test–retest reliability for all except PROMIS Cognitive Function and PRO‐CTCAE nausea. Large correlations were seen for the same domain across measures while correlations for divergent domains within a measure and different domains across different measures were small. The PRO‐CTCAE items showed small to medium correlations with each other and with PROMIS and SF‐36 domains. Stage was associated with physical function, fatigue, social roles, swelling, and shortness of breath scores.ConclusionThe AL‐PROfile has acceptable reliability and validity for use in systemic light chain amyloidosis patients.