Background:Thalassemia Major Disease is not only assumed as a health disorder, but also a social- economic problem in many countries. The costs of transport and preparation of drugs is considered as the greatest problems for more than 63.8% of the patients’ families.This study was conducted by aiming at describing biological experience among parents of patients with Thalassemia Major.Method:The current qualitative investigation was carried out on 32 parents of patients with Thalassemia Major and by means of unstructured interview in- depth through snowball sampling technique in 2013. The data were analyzed by conventional content analytical method.Findings:The perception of biological experience of parents of patients with Thalassemia Major were classified based on participants’ experiences into three main themes including psychological experiences, physical experiences, and social experiences. 1) Psychological (mental) experiences comprise of two subclasses of the reduced self-confidence, deficient emotions and negative emotions; 2) Physical experiences consist of three subclasses of sleeping disorders, pains in various parts of body, and limited physical activity; and 3) Social experiences includes 3 subcategories of interpersonal relations, reduced income, job, and limitation in doing tasks. 4) Treatment experiences comprise of five sub-themes including 1- Shortage of drugs, blood, and filter etc; 2- Less experienced personnel; 3- Lack of training the patients’ parents by personnel in thalassemia ward; 4- Lack of visiting patients by physician in thalassemia ward; and 5- Inappropriate behavior of personnel toward patients and their parents.Conclusion:Thalassemia Major has affected negatively on several fields of health for these patients and their parents including physical, mental, economic, and social areas. Reducing these problems requires constant interventions and surveying health and medical status of these patients.