OBJECTIVESA health-promoting lifestyle (HPL) is a factor that affects the quality of life (QoL) in patients with beta-thalassemia (β-thalassemia). Due to the lack of studies of this issue, this study aimed to determine the association between HPL and QoL among adults with β-thalassemia.METHODSThis cross-sectional (descriptive-analytic) study was conducted among 389 adult patients with β-thalassemia in Tehran, Iran. The research instrument included a questionnaire consisting of three parts: demographic items, the Short-Form Health Survey and the Health-Promoting Lifestyle Profile. The data were analyzed using SPSS version 23.0. The results were considered significant at the conventional p<0.05 level.RESULTSThe mean age of the participants was 30.2±8.3 years. The mean score of the HPL dimensions was 127.28±21.53, and the mean score of the QoL domains was 61.44±23.38. The highest and the lowest mean scores of the HPL dimensions were found for spiritual growth (23.96±5.74) and physical activity (11.32±3.95), respectively. The QoL scores in all three domains (total, physical component summary score, and mental component summary score) were moderate. Health responsibility, physical activity, spiritual growth, and interpersonal relations were significant predictive factors of QoL in adults with β-thalassemia; these four dimensions explained 37.9% of the variance in QoL.CONCLUSIONSQoL and HPL were not at acceptable levels among patients with thalassemia. Therefore, educational interventions emphasizing spiritual growth, physical activity, and interpersonal relations are necessary for patients with thalassemia.