This study was carried out to investigate the characteristics of major odorous pollutants emitted from foodwaste treatment facilities for providing the basic information in field of prevention. Twelve odorous components were analyzed at unit processes in 3 plants on May, August and October. The major odorous components appeared to be Ammonia (559.42 ppb), Acetaldehyde (229.70 ppb), Methylmercaptan (50.39 ppb) and Hydrogen sulfide (48.90 ppb). In the view-point of COC (Calculated Odor Concentration) based on odor threshold, A plant showed the highest value. The major odor active facilities were prevention ＞ input ＞ afterripening ＞ fermentation ＞ boundary ＞ pretreatment. The major odor active components were Hydrogen sulfide, Methylmercaptan, Acetaldehyde and i-valeraldehyde. It is important that the findings on major odor active facilities and components should be referred in the design of odor treatment process to the specific plants.