Background: Balanced and adequate nutrition is important to improve the quality of life of children with intellectual disability but most of these children are negatively affected by nutritional problems. Objective: This study was conducted to determine the nutritional status and effect of the severity of intellectual disability on nutritional status of children and adolescents with intellectual disabilities. Methods: One hundred twenty-two intellectually disabled children aged 4-18 years from five different special education and rehabilitation centers were included in the study. Their socio-demographic characteristics, body weight, height, body mass index (BMI), mid-upper arm circumference (MUAC), and skinfold thickness were examined, and their three-day food consumption record was taken. Results: Anthropometric scores did not differ significantly according to the severity of intellectual disability. According to evaluations made based on the World Health Organization's 2007 percentile curves, 61.4% of the subjects with mild intellectual disability (MID), 57.1% of those with moderate intellectual disability (MOID), and 53.3% of those with severe intellectual disability (SID) were within the normal BMI range for their age. Conclusion: Rates of malnutrition and shortness in children and adolescents with SID were found to be higher than among children with MID and MOID, though the differences were not statistically significant.