Although gastric cancer is an uncommon spontaneous neoplasm of laboratory animal species, rodents, and to a lesser extent other animals, have been used in chemically induced gastric carcinogenesis studies for decades. The role of diet in preventing or promoting gastric cancer has also been addressed in animal models. With the discovery of Helicobacter pylori and its causative role in gastric disease in humans, several animal models have been described for Helicobacter spp.-induced gastric disease, and in selected models, development of gastric and hepatic cancer. This review has attempted to highlight salient features of Helicobacter models and how these observations may be interpreted in light of data obtained from chemical carcinogenesis and nutritional studies. Further insight into mechanisms of Helicobacter-induced cancer should evolve by combining and comparing relevant features of these in vivo models.