Background and Objective: Patients with thalassemia major have an abnormality in hemoglobin synthesis and ineffective hematopoiesis and for this reason with respect to disease severity should receive one or more fresh blood unit every 15-30 days. Since transfusion of blood products has been known as one of the routes of HIV infection, therefore, this study was conducted to evaluate the prevalence of HIV infection in thalassemic patients under transfusion in Hajar hospital in 2006. Materials and Methods: Descriptive strategy of this study was conducted on 73 serum samples from patients with thalassemia major as referrals of Hajar hospital. In this respect, HIV-Ab of the samples was assessed using ELISA method. For each patient, information including age, gender, and date of 1st blood transfusion were collected. The presence or absence of HIV1 and/or HIV2 antibodies was determined with regard to absorption cut-off value. HIV-Positive samples with absorption greater than 0.8 were further studied using PCR. Results: Out of 73 studied patients, 36 and 37 cases were male and female respectively. The mean age of patients was 10.3 ± 4.9 years. All of the patients had blood transfusion from 1991.The prevalence of HIV-positive in these patients was 0%. Conclusion: This result can be attributed to probably low incidence of HIV in blood donors and precise screening of blood products by Blood Transfusion Organization.