Background: In serious competitions in order to keep the acquired fitness, athletes are advised to reduce the exercise intensity before starting the races. This technique is called taper. The purpose of this study was to compare four usual procedures of Taper and effect of them on the Hematological responses by measuring Vo2 max, hematological and biochemical factors. Methods and materials: Sixty semi professional athletes, 20 to 35 years old with Vo2 max between 30-45 three milts/kg/min were selected. Exercises were in three stages and took for eight weeks. In the first stage, which lastd for 4 weeks athletes did moderate intensity exercise three days a week and 30 minutes a day. Second stage started after the first stage with vigorous exercise three days a week and 45 minutes a day that lasted for two weeks. In the third stage taper, the subjects were randomly divided into four groups. The program of the first group was two days week and exercise intensity so was done with 85%, 75%, 65% and 55% of maximum exercise intensity. Second group program was two days a week exercise with 50% of maximum exercise intensity. The third group program was two days a week exercise with gradual reduction of exercise intensity. The fourth group had only rest. At second and sixth weeks after doing progressive exercise and taper, blood samples were taken from the cases and were sent to a reliable diagnosis lab.Results: Collected data from different taper methods were analyzed using repeated measures ANOVA and no significant difference between biochemical factors (P>0.05) was seen but the data showed a significant difference among Vo2 max values after using theses methods (P=0.04). In addition, there was significant difference in hemoglobin, hematocrit, M.C.H, M.V.C, platelets, W.B.C and Vo2 max when measured in second week, sixth week and later on Taper (P<0.05).Conclusions: According to the results of this study, taper III has a considerable effect on semi professional Hematological responses.