Tehran University of Medical Sciences Journal of Pharmaceutical Care 2322-4630 10 4 2022 12 31 223 228 EN Azita Azarkeivan Blood Transfusion Research Center, High Institute for Research and Education in Transfusion Medicine, Thalassemia Clinic, Tehran, Iran. Ghader Mohammadnezhad School of Pharmacy, Shahid Beheshti University of Medical Sciences, Tehran, Iran. Hadi Esmaily Department of Clinical Pharmacy, School of Pharmacy, Shahid Beheshti University of Medical Sciences, Tehran, Iran. 2022 10 19 2022 11 23 Background: Thalassemia is a congenital disease and Iran is as one of the countries in the thalassemia belt. It has a huge burden in Iranian national health budget. The aim of this study was to develop a questionnaire to assess the knowledge and practice of thalassemia patients toward their medications.  Methods: This is a methodological research, which was done from April 2020 to November 2021 in Tehran, Iran, to develop a valid and reliable instrument for measuring major thalassemia patients’ knowledge and practice regarding their medications, a questionnaire based on three iron chelating medications (deferoxamine, deferiprone, and deferasirox) developed. This process done by holding several expert panel meetings. This questionnaire was consisting of some aspects such as: administration, self-monitoring, miss dose, common interactions, and adverse events. Content validity index (CVI) and internal consistency and reliability were calculated.  Results: The CVI was as 0.76 for deferoxamine, 0.80 deferiprone and 0.88 for deferasirox questionnaire. Further analysis for internal consistency demonstrated satisfactory results with Cronbach’s alpha coefficients ranging from 0.743 to 0.781. Results showed Thalassemia Medication Questionnaire (TMQ) demonstrated acceptable validity and reliability for application.  Conclusion: It was concluded that TMQ could be a useful instrument to measure knowledge and practice about iron chelation therapy. The reason is the diverse range of questions and the simplicity, validity, reliability, and the practicability. https://jpc.tums.ac.ir/index.php/jpc/article/view/541