Primary intestinal lymphangiectasia is a rare clinical condition of unknown etiology. The common age of presentation is during the first 3 years of life, but cases in adults have also been reported. It has a variable symptomatology, but the main clinical manifestation is edema, also diarrhea and weight loss can occur. The loss of lymph fluid into the gastrointestinal tract also leads to hypoproteinemia and lymphopenia. Diagnosis is based on clinical manifestations, laboratory and endoscopic findings, and is confirmed on histopathological examination of biopsy. The main treatment is a protein rich, low in fat and medium chain triglyceride diet. We present the case of a 1-year-old male patient who presents with generalized edema, predominantly in lower limbs, and diarrhea. Laboratory findings show the presence of marked hypoproteinemia. Then an endoscopy and a duodenal biopsy are performed, and the histopathological study confirms the diagnosis of primary intestinal lymphangiectasia. The patient is treated and after a satisfactory evolution, is discharged.