Background. Autism is a spectrum of neurodevelopmental disorders with manifestation within 3 years after birth. Manifestations of autism include behavior problems (hyperactivity, toys destruction, self-harm, and agression) and sleep and eating disorders. Etiology of autism is poorly understood. Oxidative stress and antioxidants can participate in pathobiochemical mechanisms of autism.Methods. Twenty-four children, aged 3–6 years, with autism according to the DSM IV criteria and using CARS were included in the study. Concentrations ofCoQ10-TOTAL,γ- andα-tocopherol,β-carotene, and lipid peroxidation were determined in plasma before and after three months of supportive therapy with ubiquinol at a daily dose2×50 mg. Data on behavior of the children were collected from parents at the same time.Results. Ubiquinol supportive therapy improved symptoms in children with autism, as communication with parents (in12%), verbal communication (in21%), playing games of children (in42%), sleeping (in34%), and food rejection (in17%), withCoQ10-TOTALplasma level above2.5 μmol/L.Conclusions. Beneficial effect of ubiquinol in children with autism has been demonstrated for the first time. We assume that plasma concentration ofCoQ10-TOTALand lipid peroxidation could be used as relevant biomarkers of ubiquinol supportive therapy.