We analyzed hair concentrations of magnesium (Mg), calcium (Ca), copper (Cu), zinc (Zn) and iron (Fe) in a group of 82 children with mental retardation, in which 9 patients suffered from epilepsy, 18 from Down's's syndrome and 55 from cerebral palsy. Girls comprised little over 50% of the patients.In a group of boys with epilepsy we found a Mg, Ca, Cu and Fe deficiency, and normal level of Zn. In a group of girls with epilepsy, apart from low Fe concentration, a high levels of Ca, Mg, Zn, and Cu was noted.In girls with Down's syndrome a high or normal level of Ca, Mg, Zn and Cu was found, whereas Fe concentration presented itself in a non-characteristic way.Both boys and girls, in the group of children with cerebral palsy had low Fe concentration, as well as low Cu levels was found in older patients. In this group we also noted high concentrations of Ca, Mg and Zn in girls and normal in boys.A high concentration of Ca in girls with cerebral palsy requires separate analysis.Obtained results could be useful as a guidance in the direction and determination of the amount of possible supplementation.