The purpose of this study was to examine the experiences of young children s in the course of appreciating picture books, talking about cooperation described in the picture books, making cooperative group games based on the picture books through group discussions and performing the game activities in collaboration. For this purpose, following research question was set up. 1. What experiences do young children gain while they engage in young children-led group game activities by using cooperation-related picture books? Participants for this study were 24 young children(12 boys and 12 girls) in a class at a kindergarten attached to K elementary school in the city of K, North Gyeongsang Province. They were at the Western age of five. This study was implemented during a 10-week period of time from April 23 to June, 27, 2013. Overall, they engaged in the activities 27 times. Data was gathered in diverse ways. The video materials were transcribed by using triangulation(Merriam, 1988) that was a method to improve the validity and reliability of a qualitative research, interview, and the photographs of the young children s activities, this researcher s observational journal and the results of their activities were all collected. As for data analysis, the video materials were transcribed, and the collected data was integrated, classified, analyzed and interpreted. The results of this study are as follows: The experiences that the young children had while engaging in the cooperative group game activities by using picture books were categorized into five: “knowing that the cooperative group games were more pleasant than competitive games,” “finding it more delightful to play the group games that they made together,” “finding it joyful to share opinions about diverse methods of the games without being concerned about victory or defeat,” “becoming good friends while solving the problems together,” and “cooperating with one another to attain the common goal.” First, the young children found that the cooperative group games were more delightful to play than competitive games as they continued to make and fulfill cooperative group game activities on their own. Namely, they realized that there could be enjoyable results when they understood one another and felt happy about the process of tuning different opinions and of doing the activities, and that it s happier to play group games in collaboration than to compete with one another. Second, the young children found it more pleasant to play the group games that they made together, as they realized that the cooperative game activities were more enjoyable than competitive games. While they made the games together, they learned that things which were difficult to do alone could be more easily done by discussing with others and by joining forces. Moreover, they learned that they should share their ideas to find a better way so that they could find it happier to play the cooperative group games together. Third, the young children felt that sharing their ideas of how to play the games was more delightful than merely winning the games. Namely, they learned that they should share their diverse opinions to make both the process and results of the games more enjoyable, and they actually felt joy when they shared their ideas. Fourth, they learned to enjoy both the process and results of the games, and found it delightful to communicate with one another. And they learned to join forces to solve problems that took place in the course of playing the group games, and they finally became good friends. When they tried to solve the problems that occurred during the cooperative group game activities, they got closer to one another and naturally realized that they could help each other and were eventually in mutually complementary relationship. Fifth, they were better able to collaborate with one another to achieve their common goal. They joined forces to solve the problems that occurred durin