Background:Type-1-diabetes (T1D) also known as insulin-dependent diabetes mellitus (IDDM) or juvenile onset diabetes results from the progressive destruction of pancreatic beta cells resulting in insulin deficiency. Genetic factors are thought to be a major component for the development of T1D. The studies on the risk of developing T1D suggesting that the environmental factors, particularly viruses may be implicated in the initiation of beta cell destruction leading to T1D.Objective:To investigate the possible relationship between Epstein-Barr virus and T1D.Methods:The sera were collected from 56 T1D patients and 30 controls of age range 3-22 years old and from both sexes. The sera divided into two parts, one part for serology for detection anti-EBV EBNA-1 IgM and IgG antibodies by enzyme linked immunosorbent assay (ELISA) technique and the other for viral genomic extraction and conventional polymerase chain reaction (PCR) to detect the viral target gene.Results:The results by ELISA technique indicated that only 7 (12.5%) of T1D patients were positive for anti-EBV IgM antibody and 24 (42.9%) of T1D patients showed positive results for anti-EBV IgG antibody. In contrast, the control group showed negative results for both anti-EBV IgM and IgG antibodies. The results of PCR technique revealed that 15 (26.79%) of T1D patients have EBV DNA compared with none of the controls have EBV DNA (P<0.001).Conclusion:EBV infection may contribute to the pathogenesis or progression of T1D.Keywords:EBV, Type 1 Diabetes Mellitus, ELISA, PCRCitation:Mohammed AH, Sabr AI. THE possible association between Epstein-barr virus and type 1 diabetes mellitus. Iraqi JMS. 2019; 17(3&4): 175-182. doi: 10.22578/IJMS.17.3&4.3