Abstract: Objective : To detect upper gastrointestinal carcinoma in Northern China, a region at high risk foresophageal cancer; to formulate an explanation for this phenomenon; and to discuss the possible implicationsfor research and prevention of the centralized occurrence of esophageal cancer. Methods : We analyzed the in-cidence of esophageal cancer, gastric cardia cancer, and non-cardia gastric cancer between 1988 and 2002in four counties (Cixian, Linzhou, Yangcheng, and Shexian). According to previous results of immigration stud-ies, epigenetic epidemiology and the Darwinian theory of evolution, we put forward a hypothesis for the etio-logical factors of esophageal cancer and discussed the importance of primary prevention through improve-ment of drinking water. Results : Esophageal squamous cell carcinoma, gastric cardia cancer and non-cardiagastric cancer constituted about 70%-80% of the total cancer incidence in all of the above four counties. Thetopography varied geographically. The incidence of gastric adenocarcinoma was higher in the mountainous ar-eas, while the incidence of esophageal squamous cell carcinoma was relatively lower in the mountainous ar-eas. This geographic variation seemed to be related to the regional variation of nitrosamines. Conclusion : Thishypothesis satisfactorily explains the findings of immigration studies regarding incidence of esophageal can-cer and it has meaningful implications for research and prevention.