This study was conducted to evaluate the effect of gamma irradiation (0.4, 0.6, 0.8, 1 and 1.5 kGy) on the microbiological, physicochemical and sensory qualities of imported orange during storage at $3^{circ}C$ for 60 days. Total aerobic bacteria and yeast/mold counts in non-irradiated oranges were 3.59 and 3.75 log CFU/g, and those counts in irradiated oranges at 1.5 kGy were decreased by 1.75 and 2.26 log CFU/g, respectively. Moreover, those counts were decreased significantly according to a dose-dependent manner after gamma irradiation. The pH revealed no significant difference between the control and irradiated samples; however, titratable acidity was decreased significantly according to a dose-dependent manner and storage time. The vitamin C contents were decreased significantly according to a dose-dependent manner and storage time after gamma irradiation. Further, sensory evaluation testing revealed no significant difference between the control and irradiated samples, except 1.5 kGy. Samples irradiated at 1.5 kGy had the lowest values in color, sweetness, sourness, flavor, texture and overall acceptance. The results suggest that gamma irradiation was effective for ensuring microbiological safety; however, irradiated oranges at 1 and 1.5 kGy did not have good physicochemical and sensory qualities. Therefore, we can use the sample irradiated at 0.4~0.6 kGy as optimum-dose to be minimize on quality changes.