PURPOSE: The purpose of this study is to identify how the body composition changes after jump-roping exercise. METHODS: The subjects are 40 college students, 20 females and 20 males. The subjects were selected among college students who had not taken any drug for more than 4 weeks before the experiment started. The experiment was performed for 4 weeks, from May 23rd to June 13rd, 2012. To collect the data, the vital signs such as pulse, blood pressure, weight), and the body composition were measured before and after the experiment. The data on the body composition were analyzed by the electrical resistance analyzer. RESULT: Muscle mass was increased and body fat was decreased for both females and males after the exercise. In particular the increase of the muscle mass and the decrease of the body fat for the females were statistically significant. The result that the body fat of the females was decreased significantly more than that of males is interpreted that the body fat of females are comparatively higher than that of males. Additionally the muscle mass of the left arm and leg of the subjects were significantly increased(p<.05). Correlation analysis between general characteristics such as body composition, abdominal obesity and specific muscle areas for both men and women showed generally positive between before and after the jump-roping exercise (p<.05, p<.01). However the correlation between sleeping time and each variable showed negative. CONCLUSION: A according to the result of this study, jump-roping exercise had a very positive effect on the body composition. The study suggests that college students keep jump roping for a long period to change their body composition favorably.