Sera of 101 patients with histologically confirmed gastric cancers were investigated for parietal cell antibodies, which are the serological markers of chronic atrophic gastritis type A. These autoantibodies were more often found in patients with early than with advanced gastric cancers. They were more frequent in intestinal than in diffuse gastric cancers. It is discussed that in advanced cancers the frequency of parietal cell antibody is diminishing because of loss of antigene or binding of antibodies in immune complexes. Early gastric cancers therefore seem to be more suitable than advanced cancers to study the relation between gastric cancer and gastritis type.