This current study was designed to determine the effects of in vitro exposure to radioactive cesium-137 on human blood components. Whole blood samples were given a radiation dose of 0.02, 0.05, 0.1, 0.2, and 0.3 mGy of gamma radiation using a 137Cs radioactive standard source. The whole blood samples that were exposed to 0 mGy served as sham-controls. The spectrofluoroscopic technique was used to determine the autofluorescence spectrum of protein in plasma or red blood cells by using excitation wavelength and range of emission wavelengths at 280 nm and 300-550 nm, respectively. The hemolysis of red blood cells was evaluated by determination of the release of hemoglobin from the red blood cells to the supernatant. Complete blood counts were also determined in whole blood. The results showed that there was no change in the ratio of fluorescence emission intensity at 340 nm of wavelength of protein extract from irradiated whole blood or red blood cells compared to the corresponding non-irradiated control. The hemolysis value did not change in irradiated whole blood when compared to the corresponding non-irradiated group. In addition, complete blood count values in irradiated groups did not differ from non-irradiated group. These current results suggested that there were no harmful effects of the low-dose gamma radiation from radioactive 137Cs on blood components when human whole blood was exposed to gamma radiation in an in vitro condition.