This study was done to examine knowledge about. and need for sex education among university students in Korea. This Study design was descriptive survey design. The data were collected from 540 university students from June 10 to June 30, 1996, using questionnaires developed by the authors. The results are as follows : Those who had sex education had higher scores in sex knowledge than those had not had sex education. The average score for sex knowledge was 71.9 of a maximum score of 100. Knowledge of sexually transmitted disease was scored highest of 79.8, and knowledge of the anatomy and physiology of the reproductive system was scored lowest at 60.9. The subjects who answered 'yes' about the necessity of sex education numbered 529(98%) and the most important reason given for needing sex education was to cope well with physical and psychological developments. Regarding the content of sex education, a choice of relevant contraceptive methods was given the highest rating. Anatomy and physiology of reproductive system was the least chaser subject as the first priority among five topics. Yet, sex education for university students should include anatomy and physiology of the reproductive system, considering the low level of knowledge on this topic in the subjects of this study and its importance as a part of sex education.