Purpose : The purpose of this study was to investigate the experiences of masturbation among high school students. Method : The subjects were 925 high school students in Busan. Masturbation experience, hygienic management and physical, psychological condition after masturbation were measured. The data was collected from December 1998 to February 1999. The collected data was analyzed with frequency, percentage, mean, $x^2$ -test, t-test. Result : 1) There were significant differences in masturbation experiences according to frequency($x^2$=547.94, p=.000), educational participation($x^2$=12.11 p=.001) and hygienic management(t=3.661, p=.001) between boys and girls. 2) Contact of lewd mass media stimulated students to do masturbation and they used various methods such as stimulating genital area by using hand or tools, fantasizing about sex 3) Subjects reported that they experienced fatigue, sleeping disturbance, decreasing concentration and learning desire after masturbation. Conclusion : This study suggests that replicate studies are needed. The results are also useful in developing various sex education program.