Although the ionizing radiations cause various disorders in different parts of the human body, the importance and extensiveapplication of radiations in medicine are undeniable. In this study, we have tried to evaluate the effect of radiation on immunological and hematological parameters in the radiation workers compared with the control group. Two groups including radiation workers (test group) and a control group were determined. Test and control groups were selected from imaging staffs in teaching hospitals of Hamadan and healthy employees working in other parts of the hospital, respectively. They were matched according to age and sex. The serum levels of cytokines IFN-γ, IL-4, IL-10 and IL-17 were determined and the results were analyzed by using SPSS 18. The obtained results indicated that the level of the IFN-γ and IL-10 in the radiation workers were significantly lower than the control group (P <0.05). There was a statistically significant difference in the white blood cell count and percentage of peripheral blood lymphocytes between the radiation workers and the control group (P <0.05). Based on the results of this study and comparison with the results obtained from other studies, the effects of ionizing radiation (in the radiation workers) appear certain on blood and immune systems. However, type, the exact location and severity of the effect, require more extensive researches on the number of people under study.