Aim: Carbohydrates have important effects on the development and function of the nervous system. Wepropose to determine the effect of type I diabetes on cognitive functions of school-age children.Materials and Methods: The research was conducted on 29 children with type I diabetes mellitus.Subjects were chosen from amongst the patients who were admitted to the pediatric endocrinologydepartment of Turgut Özal Health Center (Malatya, Turkey). In addition, 28 children without anyapparent health problems were chosen as controls.Subjects were divided into four groups according to their age; two of these groups includedchildren with diabetes and the other two the controls. Wechsler intelligence test, which wasdeveloped for children, was applied to control and patient groups by pediatric psychologists.Results: We identified that type I diabetes influenced the abilities of visual-spatial groups indifferent ways. We observed that it was influential on visual-hearing remembrance and ability toemploy acquired knowledge of various age groups of children with numerous intelligence types. Ingeneral, we noticed statistically significant differences in word sequencing, picture completion anddesigning the picture abilities between the groups. A positive correlation was identified betweenthe cubical figure and performance scores ofthe two diabetic children groups.Discussion: We reviewed the results in the light of the relevant literature. Diabetes was found toaffect specific type of memory inversely. Therefore, it can be concluded that time of diagnosis andensuring metabolic control in diabetes might have important consequences associated with thehazardouseffectsofdiabeteson thedevelopment andfunctionofthenervous system.