A case study of a baby girl is presented who was born through cesarean section, and developed protracted diarrhea and metabolic acidosis after three days of her birth. The infant was treated with intravenous fluids as well as antibiotics after obtaining blood and stool cultures. The baby's serum anion gap (sAG) was calculated, in which there were no clinical or laboratory findings of sepsis, and serum lactate was normal. Renal tubular acidosis (RTA) was characterized by normal sAG hyperchlomeric metabolic acidosis resulting from either impaired HCO3-reabsorption or impaired H+ excretion. The baby was identified with microvillus inclusion disease (MID), in which the patient have poor prognosis and remain dependent on parenteral nutrition. The only treatment for the patient suffering with this disorder is a small bowel transplantation.