The purpose of study was to reveal the relation between users' life style and their preference for the packages of organic soy sauce, using data mining techniques. Fifty-six adults in their 20s to 60s answered about the life style and judged whether they wanted to buy representative samples of the current market. As a result, independently of the purchase frequency of organic foods, all participants liked the luxury ornamental package. On the other hand, there were some samples showing the contrast of preference between the core users and not-buy people. A decision tree analysis and a market basket analysis revealed rules to show who wanted to buy the samples. It was the package using green color as a code of organic foods that people who pay attention to package design wanted to buy. The package for next purchasers, that for housekeepers, and that for knowledgeable individuals were also revealed. The present study revealed 6 suggestions for new package design of the organic soy sauces.