SUMMARY Objective: To identify the feeding characteristics of malnourished children with metabolic acidosis. Methods: Observational, crosssectional study in 20 patients under 15 years of age with diagnosis of malnutrition. The patients were divided into two groups: A: 12 children with metabolic acidosis and B: 8 children with no metabolic acidosis. Food intake was evaluated by a 24 hours reminder during 7 consecutive days and frequency of consumption. Anthropometric data, venous gases, serum electrolytes, blood chemistry, urine analysis and complete blood count were analyzed. Results: Nutrient intake showed statistical difference between the two groups. Height was significantly lower in malnourished children with metabolic acidosis than in children with no metabolic acidosis: z score -1,15±0,73 vs -0,21±1,18 (p=0,04). Children with metabolic acidosis had increased intake of cheese, milk, red meat and low consumption of fruits, vegetables and legumes. Children with no metabolic acidosis had a high intake of fruits, vegetables and legumes and low consumption of eggs, red meat and milk. Although energy, protein, fat and carbohydrate intake was higher in children with metabolic acidosis, the difference was not significant. Malnourished children with metabolic acidosis consumed higher amount of non-volatile amino acids with greater potential acid load such as methionine and cysteine. This difference in both amino acids intake between the two groups was significant (p=0.000 for methionine and p=0,030 for cysteine). Conclusions: Intake of non volatile aminoacids was higher in malnourished children with metabolic acidosis. This difference may explain the generation of metabolic acidosis in some malnourished