The syndrome of protracted diarrhea (PD) includes several diseases with diverse etiologies. This study was conducted to characterize the spectrum of causes, clinical manifestations, and the outcomes of PD. A retrospective analysis of the clinical and pathological findings was performed on 25 patients with diarrhea starting within the first 2 yr of life and a requirement of parenteral nutrition (PN). According to the intestinal histopathology, patients were classified into four groups: immune enteropathy (12 cases), lymphangiectasia (6 cases), epithelial dysplasia (5 cases), and unclassified (2 cases). All patients with epithelial dysplasia had earlier onset of diarrhea and longer duration of PN than those in the other groups. Three patients (12%) had an evidence of a familial condition. Five patients (three with microvillous inclusion disease and two with immune enteropathy) died. Sixteen patients recovered, and three (two with primary lymphangiectasia and one with microvillous inclusion disease) still had diarrhea. One patient underwent intestinal transplantation for tufting enteropathy. In conclusion, infants with PD should be referred to specialized centers where advanced diagnostic and therapeutic facilities are available, because histological analysis is critical for the diagnosis of PD, and PN or intestinal transplantation is the only therapeutic option in a subset of cases.