To improve our understanding of the entity of small-cell carcinoma (SmCC) of the gastrointestinal (GI) tract. A MEDLINE search was done, using the terms "small cell carcinoma" or "oat cell carcinoma" combined with "gastrointestinal" or with any of the GI sites, for the period 1970 to 2003. The 138 eligible reports identified in this way were reviewed for clinical data. To date, approximately 544 cases of GI SmCC have been reported. The disease represents 0.1% to 1% of all GI malignancies, with the esophagus being the most common primary site. A majority of patients present with overt distant metastases. Systemic symptoms are common; ectopic hormonal secretion may occur. By light microscopy, GI SmCCs are essentially indistinguishable from primary pulmonary SmCC. The presence of non-SmCC components is common. Data from molecular analysis of the disease has identified some similarities to pulmonary SmCC. Chemotherapy represents the main treatment option, with modest impact on survival. In locoregional disease, the literature suggests that treatment be initiated using chemoradiotherapy and then, if metastatic disease is still excluded, surgical resection be considered. The disease is highly aggressive, and survival is in the range of several weeks for untreated patients and of 6 to 12 months for those receiving therapy. SmCC of the GI tract is a rare and lethal disease. Although there are many similarities to pulmonary SmCC, some differences between the two entities are suggested. While chemotherapy can achieve significant palliation, surgery may have a potential impact on long-term survival of patients with locoregional disease.