With the improvement of nutritive conditions and the influence of abundant information as well as various cultural aspects imported from foreign countries, puberty develops more rapidly in the body today. This study was conducted to suggest some ideas that are useful in planning sexual education programs in middle schools with ultimate aim being to promote sexual health. The subject of this survey consisted of 534 fifth graders from 4 schools in Hongchon. The major findings are summarized as follows: 1. The degree of sexual knowledge of adolescents showed a low average 31.00 and the degree of sexual attitude showed an average of 62.0. 2. With respect to demographic characteristics, there were statistically significant differences in sexual knowledge according to the following: living with parents (t=5.913. p=.015), father's education(F=3.213, p=.041), economic status (F=5.073 p=.007); and in sexual attitudes. there were statistically significant differences according to father's education (F=3.912. p=.002), and interest in the other sex (F=3.292, p=.038). 3. The level of sexual knowledge and sexual attitude of adolescents was correlated at significant levels(r=.354. p=.000). The findings of this study indicated that a variety of systematic sexual education programs suitable for each stage of adolescence should be developed along with family, society, and the country's higher concern and enlightenment.