Abstract: This study aimed to compare four different tapering techniques to find out their effectiveness on hematological responses including biochemical, hematological and VO2 max indices. Sixty semi-professional athletes (age 20-35 years old) and with VO2 max 30-45 mL/kg/min were recruited in this study. The test was carried out in three steps. At first step, all subjects passed a four-week mild exercise and in the second step the subjects were carry out a two-week vigorous exercise and the heart rates were recorded. In the third step, the subjects were randomly divided into four groups. Taper 1 group`s was asked to carry out exercises; two sessions per week and the intensity of the exercise was set at 85, 75, 65 and 55% of their vigorous exercise`s intensity. Taper 2 group`s task included two sessions training per week while the intensity reduced to 50% of their vigorous exercise`s intensity. Subjects in Taper 3 were asked to carry out two sessions exercise per week with gradually reduction in intensity. Subjects in Taper 4 group did no exercise. Blood samples were taken from the subjects at weeks two, six and after the tapering. In terms of the laboratory tests, ANOVA tests showed no significant differences among the Taper groups. However, a significant difference was found in the average VO2 max among the four Taper groups (p = 0.04). Based on the findings of this study, it can be concluded that Taper 3 could significantly change the hematological factors in semi-professional athletes.