The purpose of this study is to design t-shirts by using doggaebi patterns as traditional cultural products. Byuksa has the meaning of keeping away wicked spirits and to receiving good fortune. Most of the pictures of magpies, tigers, dragons, hawks, and roosters contain the meaning of protection and the doggaebi pattern is a typical Byuksa pattern. By way of example of product development, this study will develop designs by using doggaebi patterns and promote beautiful Korean traditional patterns as well as Korean traditional culture. The reason for choosing the T-shirt is because T-shirts are a basic item that all people have and wear, so Koreans and foreigners get interested in them and buy them. This study presents designs for 5 kinds of t-shirts for adults and another five kinds for kids using doggaebi patterns. This study was limited to the doggaebi pattern, so it is expected more studies about patterns and many cultural products will develop.