The purpose of this study was to investigate the effects of two weeks of detraining on somephysical fitness indexes and lactate dehydrogenase (LDH) and creatine phosphokinase (CPK)enzymes in blood serum of elite taekwondo players. Sixteen elite male taekwondo players withthe averages of age of 18/43 ± 1/20 years; weight 64/49 ± 3/03 kg and years of experience 6/46± 1/36 years were selected voluntarily based on interviews and questionnaires and all of themwere participated in taekwondo training for four weeks equally. Then the subjects were dividedrandomly into an experimental and control groups. The experimental group had a two-week detraining;while the control group continued its training program. To calculate of anaerobicpower and speed (physical fitness indexes) were used consecutive vertical jumps (Ergojump)test for 30 seconds and speed 40 yards test in two phases (Before and after of detraining). Bloodsamples to determine the desired enzymes were taken in before and after of detraining following12 to 14 hours of being empty-stomached. Data was analyzed via dependent and independent ttestin significant level P ≥ 0.05. The results of this study have demonstrated that two weeks ofdetraining caused insignificantly decrease of anaerobic power (P = 0/057) and significantly decreaseof speed (P = 0/001) in taekwondo players. Also it was observed that the levels of CPKand LDH blood have reduced significantly (P = 0/001) after tow weeks of detraining. Based theabove finding; it can be claimed that two weeks of detraining have a negative effect on speedand levels of CPK and LDH blood in taekwondo players.