Introduction: The aim of this study was to assess the effect of four weeks of high intensity aerobic interval training on blood and functional factors in soccer players. Methods: 18 soccer players in Azadegan league competitions were experienced and randomly divided into two groups (training;12 players , control;6 players). Mean ± SD age, height, weight and percent body fat were 21.88±2.24 years, 174.22±5.33 cm, 67.77±5.7 kg and 12.38±3.29, respectively. Four weeks of high intensity aerobic interval training was performed three times a week at the end of the soccer training sessions. The values obtained before and after the training period were compared using un-paired Student’s t–test, repeated measures ANOVA and LSD post hoc procedure. Results: Findings showed that 4-week training period did not cause significant changes on maximum and minimum anaerobic power and fatigue index. The only significant increase was related to mean anaerobic power. Conclusion: In addition, this training period did not have any significant effect on lactate to pyruvate ratio. We can conclude that four weeks of high intensity aerobic interval training probably did have significant effect on anaerobic power and have little effect on aerobic metabolism in soccer players.