Background: The measurement of trace elements in human body has proved to be of great use in the evaluation of human health and the diagnosis of various diseases. No light, however, has been shed on these elements where they concern the human intelligence. Objectives:The goal is to make a comparison between the students with a lower IQ and those having an ordinary IQ in terms of the amount of zinc and copper as two trace elements. Methods: This is a case-control study and the subjects as the patients were chosen from mentally retarded students having no particular diseases. The sample size for the patient and control was 30 for each. The hair samples of the experimental group and the ordinary students (the control group) were digested with concentrated HNO3 after being washed with water and acetone. After being digested, the values of zinc and copper in the samples were measured with atomic absorption spectroscopy. The obtained data were analyzed using SPSS-15 via two independent sample tests of significance tests.