The presence of rare paraneoplastic syndromes, the opsoclonus-myoclonus-ataxia syndrome (OMA), presumably caused by antineuronal antibody production, and diarrhea, caused by vasoactive intestinal peptide (VIP) secreted by neuroblastoma, may strongly signal the presence of neuroblastoma. The authors describe a child who presented with both syndromes concurrently; this has never been described previously in the same patient. However, diagnosis of neuroblastoma was delayed by a workup focused on the prolonged diarrhea rather than the ataxia. The diarrhea resolved after tumor resection, whereas OMA required further therapy. Increased awareness of VIP-secretory diarrhea, especially in an ataxic child, might contribute to an earlier diagnosis of neuroblastoma.