The aim of this research was to determine the affect of the 8 weeks dynamic strecthing exercises on the improvement of flexibility of the 10-12 years competitor female swimmers. Subjects were voluntarily participated in this study. Subjects were divided into two gruops, these were 12 swimmers for experimental group from Galatasaray sports Club, with age of 11,08±0,7 years, body weight of 37,08±4,8 kg and height of 150,8±8,6 cm and 8 swimmers for control group from Yeşilyurt Sports Club; with age of = 10,08±0,8 year, body weight of38±3,3 kg, height of 148,8±6,5 cm. All groups participated in water and land training session, 12-18 hours in a week through 8 weeks. In addition to training periods, the Experimental group performed extra warm up activities, 3 times in a week and 12 different strecthing exercises. Each exercise was performed 3 times for 30 seconds. SPSS 10.00 for windows packet programme was used to analyze data. To analyze differences between means of groups and measures, “Independent Samples t Test and Paired t Test” were used and significant levels were accepted as p<0.05 and p<0.01. As a result of this study, it was found that there were significant improvements of left-right shoulder flexsion-extansion, left-right hip flexion-extansion, left-right plantar flexion and leftright dorsi flexion in the experimental group after 8 weeks dynamic strecthing exercises.