Introduction: Insulin dependent diabetes mellitus (IDDM) or type 1 diabetes is created by autoimmune destruction of insulin-producing beta cells of the pancreas in genetically susceptible individuals. The relationship between human leukocyte antigens (HLA) associated factors and susceptibility to IDDM disease, was reported by several investigators. Association with different HLA types depends also on the studied populations. The aim of the present study was to determine HLA antigens which represent a high susceptibility to develop the IDDM disease in this area.Materials and Methods: In this study, the prevalence of HLA class-I and II antigens has been determined in 31 Arakian patients with IDDM and 57 normal healthy controls with similar ethnic background and from the same geographical area. The typing of HLA antigens was carried out using standard microlymphocytotoxicity method.Results: A significantly higher frequency of HLA-A2, A3, B21, DR3 and DQ2 were found in IDDM cases compared to the controls. In contrast, HLA-DR2, DR7 and B53 were represented at a somewhat higher frequency in controls compared to the IDDM patients.Conclusion: These results indicate that HLA-A2, A3, B21, DR3 and DQ2 antigens contribute to susceptibility to IDDM independently and HLA-DR2, DR7 and B53 antigens maybe associated with prevention of IDDM in Arakian patients.