Clinical and epidemiological observations suggest that gastric cancer of the 'intestinal' histological type is the end result of a series of events manifested by the chronic gastritis complex. A series of progressive changes representing gradual loss of differentiation is postulated after the gastric process has reached the stage of atrophy and intestinal metaplasia. An aetiological model proposing in situ synthesis of multiple, repeated small doses of N-nitroso carcinogens is discussed.