ABSTRACT: BACKGROUND:The lower-risk (low and intermediate-1 risk based on IPSS) myelodysplastic syndrome (MDS) has a negative impact on patients' health-related quality of life (HRQoL). Patient Reported Outcomes (PROs) instruments, which are used to collect patients' HRQoL data, should have established content validity in the target population to ensure that the instrument is comprehensive and comprehensible. The present study was conducted to evaluate the content validity of the Quality of Life in Myelodysplasia Scale (QUALMS) and the Functional Assessment of Cancer Therapy-Anemia (FACT-An) PRO instruments in patients with lower-risk MDS. METHODS:In this cross-sectional, qualitative study, 16 patients aged ?18?years with lower-risk MDS, who were RBC transfusion dependent, literate and fluent in US-English were interviewed. Interviews were semi-structured comprising of two parts: concept elicitation (CE) explored symptoms and impacts important to patients, and cognitive debriefing (CD) assessed understanding and relevance of the QUALMS and FACT-An. A conceptual model was developed, which was used to map the concepts that emerged during CE onto the QUALMS and FACT-An to assess concept coverage and suitability of the instruments. RESULTS:The median age of participants was 67.5?years (range: 51-91), with half being female (n?=?8). Nine (56.2%) participants had intermediate-1-risk MDS and 10 (62.5%) were relapsed or refractory to erythropoiesis-stimulating agent treatment. Fatigue/tiredness (100.0%), shortness of breath (87.5%), weakness (81.2%), and low energy (75.0%) were reported most commonly and were the most bothersome symptoms as well. Of seven high-level HRQoL domains identified, activities of daily living (n?=?16, 100.0%), physical functioning (n?=?15, 93.8%), emotional wellbeing (n?=?13, 81.3%), social functioning (n?=?12, 75.0%), sleep disturbance (n?=?9, 56.3%), and impact on work (n?=?9, 56.3%) were the most commonly reported. For CD, the QUALMS and FACT-An were found to be mostly relevant and very well understood; response options were easy to use, and recall period was appropriate. CONCLUSION:Both QUALMS and FACT-An demonstrated a strong face and content validity in patients with lower-risk MDS, suggesting that these instruments are appropriate for assessing HRQoL in this population.