Objectives: There is an association between viral infection and development of diabetes mellitus. This study aimed to investigate the role of rubella virus, cytomegalovirus and coxsackievirus in patients with type 1 (T1D) and type 2 (T2D) diabetes mellitus in respect to the glycemic control and immune response presented by serum γ-interferon leveland antiviral antibodies. Materials and Methods: A total number of 160 (70 male and 90 female) T1D and 75 T2D (25 male and 50 female) patients allocated randomly from Martyr Layla Qasm center for diabetes mellitus in Erbil, Iraq, were enrolled in the study. Serum IgG antibody (I.U./mL) against rubella virus, cytomegalovirus coxsackievirus as well as serum interferon-g were determined. Results: Type-1 diabetic patients with positive anti-coxsakievirus antibody presented with significantly shorter duration of illness (4.822 ± 2.442 year) and poorer glycemic control (HbA1c %: 9.895 ± 1.272) This observation was not noticed with other viral infection as well as in T2D. Significant alterations in serum interferon-g (8.051 ± 13.371 pg/ml) were observed in T1D and related to coxasackievirus infection (13 patients had a level higher than 10.975 pg/ml; the upper limit of 95% C.I of control, and 34 had a level less than 4.457 pg/ml; the lower limit of 95% C.I of control). Conclusions: Subjects with type 1 diabetes and Coxsackie infections seem to have a different immunological and clinical profile. This needs further study.