Objective: To compare the dietary habits and nutritional status of mentally retarded (MR) and normal (NG) subjects and to examine the relationship between the dietary habits and nutritional status and the level of mental retardation in the MR group. Method: A case control design was utilized: 117 MR (random sampling) and 100 NG (quota sampling) subjects between 7-18 years matched for age (except in the 16-18 years age group) and socio-economic status were selected from a government and private institution, respectively. Nutritional status (energy, protein, fat, calcium, iron and vitamins A, B1, B2 and C) was assessed by the food diary method. Body Mass Index was recorded. Eating habits were obtained on a dietary habits proforma and blood samples were analyzed (hemoglobin, lymphocyte count and serum albumin). Results: More MR children were underweight, while more normal children were overweight. MR group was significantly more likely to have difficulty in chewing and swallowing; and the tendency to spit out and vomit food. Based on a cutoff of 2/3rd RDA (Recommended Dietary Allowance), diets were deficient in iron and possibly riboflavin in 10-18 year old MR males; and in iron in the normal group; however, a direct comparison of the MR and normal groups revealed that male MR subjects had significantly lower intake of most nutrients. Level of retardation was associated with self-feeding deficits. Conclusion: Diets of MR and normal group subjects were inadequate with regard to mean iron consumption; and boys with MR had significantly lower consumption of all nutrients in comparison to normal boys. (Contains 3 tables.)