This study was carried out to investigate the information concerning dietary patterns and analysis of the various factors that influence obesity. The subjects of this study were 1,020 middle and high school students in Seoul. Subjects were classified into under weight, normal weight and over weight group by body mass index. We investigated eating habits, life habits, food behavior and food consumption. Data were collected by questionnair and analysed with the SAS program. The results of this study way are summarized and concluded as fellows; In the case of dietary pattern, over weight group showed significantly higher in skipping a meal than the other group. Also over weight group tend to eat fast. There were significant differences of food intake frequency score by body mass index. From the results of factor analysis of variable related to obesity, 4 factors were generated and the factors were named 'Food behavior related to obesity', 'Snack consumption pattern', 'Life habit', 'Family environment related to food habit'. These factors were associated with obesity. To maintain nutritional balance and health, we should implement to ensure good dietary patterns.