This study was conducted in order to know the impact of coenzyme Q[subscript 10] (CoQ[subscript 10]) supplement on the muscle damage and total oxidant (TOS) enzyme levels of young skiing athletes during exercise. 15 male athletes were used for two weeks in the study. The athletes were divided into three groups: the control group and two subject groups taking 100 mg and 200 mg CoQ[subscript 10]. A maximal exercise program with 70-80% overload was applied to the groups for two hours every day for two weeks. Before (B.T.) and after (A.T.) the training, blood samples were taken from athletes in order to determine CoQ[subscript 10], TOS and aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), glutamyl transpeptidase (GG), lactate dehydrogenase (LDH), Creatine kinase (CK) enzyme activities. HPLC kit was used to determine CoQ[subscript 10] levels and TOS kit was used to determine TOS levels. When the pre-exercise and post-exercise CoQ[subscript 10] levels were compared, it was seen that CoQ[subscript 10] values of subject groups increased (p<0,05; p<0,01) while the control group did not show a significant difference. Also, a decrease was seen in TOS values of subject groups (p<0.01), whereas the control group showed an increase (p<0,01). In addition, significant increases (P<0.01) were obtained in the levels of AST, ALT, LDH and CK of the control group compared to those of the subject groups. Comparing CoQ[subscript 10] and TOS levels by days during 2 weeks, it was found that TOS levels of control group increased; no change occurred at CoQ[subscript 10] and; TOS levels of experimental groups decreased and significant increases were found in CoQ[subscript 10] groups. In conclusion, CoQ[subscript 10] usage may have impact on lower TOS values and liver, muscle enzyme activities of experimental group compared to control group.