The purpose of this study was to investigate the effects of 16 weeks of spinning and bicycling exercises on body composition, physical fitness and blood variables in female adolescents. Subjects participated in this study were 24 female middle school students (12 spinning cycles, 12 general bicycles) attending to Seoul Yeoksam middle school. Each group was trained for 16 weeks, 3 times a week, and 1 hr per day after school. Body composition, physical fitness (1,200 running, sit-ups, back strength, sit and reach, side-steps) and blood variables (low-density li-poprotein cholesterol, glucose, reactive oxygen species, and malondi-aldehyde) were examined before and after 16 weeks of training. As the results, body weight did not show any significant difference; however, body mass index, and % body fat were significantly difference in spin-ning group. The enhancement in physical fitness factors were recog-nized in both groups, which was greater in spinning group in sit-ups, back strength, and side steps. Blood parameters were significantly dif-ference between groups, but between group and time interactions were significantly difference in glucose and reactive oxygen species. In conclusion, this study suggests that 16 weeks of bicycle exercises were positive changes in body composition, physical fitness and blood con-stituents, indicating that spinning cycle is more beneficial as compared to ordinary bicycle.