Although cell proliferation studies on gastric mucosa are relatively few compared to the results obtained in the large bowel, they brought important contributions to our knowledge of the mechanisms involved in the development and progression of neoplasia. In normal gastric mucosa, the proliferative zone is limited to the neck region of the glands. In diseases at risk for gastric cancer, such as chronic atrophic gastritis, two main features have been observed: an increased cell proliferation rate and expansion or upward displacement of the proliferative compartment. However, while a high cell turnover rate can be due to many stimuli such as inflammation or the effect of hormones (i. e. gastrin), the expansion of the proliferative compartment is more evident with the development and progression of neoplasia. It could be due to an error in the control of cell proliferation and maturation. This kinetic pattern is probably a marker of gastric cancer risk. Application of these observations in clinical investigations are the search for proliferative abnormalities and other phenotypical markers in order to define an individual profile of cancer risk, and to evaluate the effects of xenobiotics or dietary intervention in controlled trials.