Campylobacter jejuni was studied for its disinfection by heat-and cold-treatment and UV-irradiation. When C. jejuni was treated by heat, no viable cell was found after 10 min treatment at $55^{circ}C$, whereas small fraction of cell population was survived after 60 min treatment at $45^{circ}C$ and $50^{circ}C$. When they were treated by cold temperature for 30 days, no cell was survived at -$23^{circ}C$ but about 4 log of the cells were survived at both temperature of $4^{circ}C$ and -$40^{circ}C$. When the organisms were UV-irradiated, thier survival rates were proportionally varied to the distance of irradiation. The scanning electron microscopic studies of C. jejuni cells treated by the disinfecting agents revealed that shapes of thecells were deformed from spiral rod into spherical form. The heat-treated cells showed rough and damaged surface on the scanning electron micrographs. In the heat-treated cells, some proteins of high molecular weight appeared to become accumulated in the electrophoretic analysis. The DNAs extracted from the cells treated with the physical agents showed some differences in agarose gel electrophoresis, comparing those of normal cells.