Purpose: This research was conducted to compare sex-related knowledge and attitude of 6th-grade elementary school students who participated in the field based learning and those with cooperative learning methods. Methods: The data were collected from June to July in 2009. The subjects of the study were recruited from the classes of the 6th grade conveniently assigned from the D elementary school located in Daejeon metro city. Total of 60 students were assigned either to the field based learning group, and the other 60 students to the cooperative learning group. The field based learning group received sex education at the Daejean Youth Sexuality Culture Center for 3 hours. And the cooperative learning group received sex education by cooperative learning method at the classroom for 40 minutes per session, once a week, for 3 weeks. The sex-related knowledge and attitude scales developed by Lee (2004) were used. The data were analyzed by $x^2$-test, Fisher's exact test, and t-test using the SPSS/WIN V. 12.0 program. Results: The results were as follows. 1. Sex-related knowledge was not significantly different between the cooperative learning and the field based learning group. 2. Sex-related attitude was not significantly different between the cooperative learning and the field based learning group. Conclusion: In this study, sex-related knowledge and sex-related attitude of the cooperative learning group and the field based learning group were different from the lecture method groups in the earlier study. It is worthy of notice that the cooperative learning group and the field based learning group took relatively less time to improve their knowlede and attitude than the earlier lecture based group did.