Gamma irradiation as a new physical treatment was applied to comparative researches with a conventional chemical fumigant on the microbiological and physicochemical qualities of selected agricultural products such as powdered hot pepper soybean paste, oyster mushroom powder, carrot flake, and raw sesame. The microorganisms contaminated in the sample, including total bacteria, thermophiles, acid tolerant bacteria, fungi, osmophilic molds and coliforms were sterilized with irradiation doses of 7-10 kGy, while ethylene oxide (E.O) fumigation proved insufficient for the destruction of them. An optimum dose of irradiation was less detrimental than E.O. fumigation to the physicochemical properties of the sample. Sensory evaluation after three months of storage at room temperatures showed that the overall acceptability of irradiated sample was higher than that of the nontreated control as well as E.O. fumigated samples.