The association of chronic diarrhea with neural-crest tumors is uncommon. In the past 12 years, we encountered three cases of neural-crest tumors presenting initially as chronic diarrhea. The incidence of chronic diarrhea in patients with neural-crest tumors at our hospital during this period was 3.8%. These patients (two girls and one boy aged between 15 to 28 mo) presented with a 3-week to 6-month history of chronic diarrhea of unknown cause. A posterior mediastinal mass or abdominal mass found on sonography and chest roentgenography eventually led to the diagnosis of neural-crest tumor in these patients. Pathology revealed ganglioneuroblastoma in two cases and neuroblastoma in one. All three patients received chemotherapy and underwent surgery. Diarrhea ceased postoperatively in all three patients. Although one of the patients died of septic shock during chemotherapy, the other two remained free of disease at 30 and 22 months of postoperative follow-up, respectively. A high index of suspicion is needed to identify cases of neural-crest tumor from the presenting symptom of chronic diarrhea.