en Hematology and Oncology Letter to the Editor Letter to the Editor <div style="text-align: justify;"><span style="font-size:14px;"><span style="font-family:Tahoma;"><span style="line-height:2;">Non-adherence to treatment is a major worldwide concern for healthcare providers. This is especially important in chronic diseases where patients have to follow the prescribed treatment for a long time. Adherence to the treatment of patients with chronic diseases in developed countries is at an average of 50%, and this rate is lower in developing countries. Despite many studies on non-adherence to treatment, it has remained an unresolved issue for the past four decades. On the other hand, commonly used interventions and practices have not successfully improved adherence to prescribed treatments in patients with chronic diseases. Moreover, the available theories of adherence have little explanatory power to justify this issue.</span></span></span><br> &nbsp;</div> Adherence, Thalassemia major, Qualitative study 95 98 http://jpr.mazums.ac.ir/browse.php?a_code=A-10-1137-1&slc_lang=en&sid=1 Zahra Soheilirad drsoheilirad@yahoo.com 100319475328460011219 100319475328460011219 Yes Department of Pediatrics, School of Medicine, Heshmatie Hospital, Sabzevar University of Medical Sciences, Sabzevar, Iran.