The purpose of this study is to establish the one serving size of Korean Processed Food. Defining the one serving size is very important for nutrition labeling and foodservice operation, because the one serving size is used to set up a proper portion by each foodservice operation. The basic data of 200 items were collected through three methods. Searching many cookbooks, exploring the commercial and noncommercial foodservices -6 industrial foodservices, 100 nationwide elementary school foodservice recipes analysis, and 3 hospital foodservice systems as the samples - moreover, experimental cooking and sensory evaluation by trained panels were conducted to assess quantity preference of selected food items. All data were rearranged through food type, that is, main dish, side dish, dessert and health food. One serving sizes of processed foods showed wide variety according to the different menus that include selected food items. Therefore, means and ranges of serving size by three research methods were presented item by item. The results obtained were: 1. The Korean Processed Foods were dried and sugar adding and soused foods, and many of them used the natual processing methods. 2. There were wide varieties in the classification of main dishes, but many of them were cereals, noodles, and sugar products. One serving size of noodles were around $50{sim}100;g$, cereals were $20{sim}40;g$, which means the one serving size can be differenciated by the food usage. 3. According to the Food classification of side dishes, many of them were as following; natural dried foods, processed fish products, salted or sugar added foods, seasoned foods and sugar products. Moreover the Types of cooking in side dishes were almost culinary vegetables, teas, health foods and condiments, and soused fish products. 4. About desserts, they were almost teas and sugars, and the Types of cooking were teas, health foods and seasonings. 5. We can conclude that almost Korean Processed foods used the drying and soused processing methods for long-time preservation, but it can make the higher content of any special elements, such as sodium or carbohydrates.