Purpose: In an attempt to measure the changes in gender-egalitarianism after sexuality education based on the gender-egalitarianism in middle school students, this study was carried out. Methods: The subjects were 137 students (67 boys and 70 girls) in 4 classes that were randomized from among 8 classes of first graders in a coeducational middle school, in Seoul. By the school nurse with the assistance of an advisory committee on sex education by the MOE, sexuality education was implemented based on gender-egalitarianism. The content was presented over 18 hours during 16 weeks, from September, 2001 to December, 2001. For the pre and post check on gender-egalitarianism, a Gender Egalitarianism Scale modified by the researcher was used. Results: After the sexuality education based on the gender-egalitarianism, there was a significant elevation in gender-egalitarianism(t=4.378, p=0.000). There were no significant differences in the mean changes in gender-egalitarianism according to religion, economy level, educational level of parents, and openness of parents. And little experiences in adult video, no experience in masturbation, and being without the opposite sex were related to significant elevations in gender-egalitarianism. The case of the having the positive sexual attitudes showed a significant elevation in gender-egalitarianism as compared with the case of having negative sexual attitudes. Conclusions: Based on these results, sexuality education based on gender-egalitarianism for youth was effective in elevating gender-egalitarianism scores. Because the case of the wide experiences with sexual behaviors showed a tendency to make low gender-egalitarianism, the education program would be effective to implement early in the school as childhood is a period in which children have a non-established sex-role.