The purpose of the survey was to Identify the degree and the relationship of sexual knowledge, sexual attitude. This information will provide useful data for a more systematic, desirable, and practical sex education. The data was collected from 187 first grade schoolchildren(95 boys and 92 girls) of two Junior high school in Chun-nam area. The data was gathered by questionnaire from Oct. 1 to 15, 1996. The questionnaire was modified by authors using the questionnaire developed by You-Jeong, Han (1996). Data was analyzed by using the statistical computer package, SAS to manipulate the data along with percentages, means, standard deviation, t-test, χ²-test, GLM, and Pearson correlation coeffiency. The results in this study were summarized as follows: 1. Sex related knowledges.-The mean score of sex related knowledges showed significant differences between boys and girls (boys : 22.3, girls .21.0, p<0.025), and in the area of pregnancy & delivary(boys : 9.4, girls : 7.9, P<0.000) showed significant difference between boys and girls, but in the area of physical differeces of the other sex(boys : 12.9, girls ; 13.1, p<0.551) showed no significant difference between boys and girls. 2. Sex related attitudes.-The mean score of sex related altitudes showed significant difference between boys and girls (boys : 56.7, girls : 60.5, p<0.002) and in the area of psychological difference the other sex(boys 28.9, girls : 32.5, p<but in the areas of form of friendship with the other sex(boys : 11.5, girls : 11.2, p<0.335), sexual delinquency & its prevention(hys : 16.3, girls : 16.9, p<0.171) showed no significant difference between boys and girls 3. The relationships between sex related know ledges and sex related attitudes.-Those who had higher sex related knowledges showed more positive attitudes towards sex, and showed no statistical significance (r=0.08, p<0.286) 4. Differences of the sex related knowledges ac cording to general characteristics.-The students had disease experience, health interest and more school performance had higher knowledge scores about sex. 5. Differences of the sex related attitudes accord ing to general characteristics. Those who were in high school performance had higher attitude scores about sex as well. From the result of the study, it is recomended to develop systematic sex education through formal school education acorrding to age.