There are many published reports suggesting a close relationship between intestinal metaplasia and gastric carcinogenesis, but there are few studies that examine the cellular kinetics of these tissues in humans. Thus, we sought to characterize the proliferative zone of intestinal metaplasia of the human stomach and correlate this with its known malignant potential. We examined the incorporation of bromodeoxyuridine into 228 human endoscopic biopsy specimens from duodenal mucosa (n=35) and non-intestinalized antral mucosa (n=127) as well as antral mucosa with intestinal metaplasia (n = 66). The proliferative zone in specimens with intestinal metaplasia was deeper when compared to non-intestinalized antral mucosa, but was more superficial than that of duodenal mucosa. Although the labeling index of intestinalized mucosa was similar to that of non-intestinalized antral mucosa, the size of the proliferative zone was significantly increased in intestinal metaplasia. The dislocation of the proliferative zone with an increase in its size in intestinal metaplasia is considered to be a hallmark of gastric intestinal metaplasia.