Conclusion. The children with S-ECC show evidence of malnutrition, particularly iron deficiency. S-ECC can be considered a risk marker for undernutrition in young children.Purpose. To describe the nutritional status of young children (N = 56) with Severe Early Childhood Caries (S-ECC) before and after oral rehabilitation.Results. Comparing Waterlow's classifications of malnutrition, 66% were ideal body weight and 33% either malnourished or overweight/obese. One-quarter was in the 10th percentile for TSF. Blood values showed evidence of protein and/or iron deficiency; 80% having low ferritin and haemoglobin. There were no observable changes in the anthropometric measurements 90-days after oral rehabilitation.Methods. Subjects were children with S-ECC having dental treatment in a hospital under general anaesthesia. Anthropometric measurements of height, weight, triceps skinfolds (TSF), and arm muscle circumference were taken pre-treatment and 90-days post-treatment. Blood tests for haemoglobin, serum ferritin and serum albumin were performed pre-treatment only. Data were compared with reference values.