Epithelial dysplasia was studied in 53 surgical specimens of gastric carcinoma and eight gastric adenomas. A spectrum of dysplasia was observed, but there were two principal types. Type I resembled the epithelium lining colonic adenomas whereas type II was composed of eosinophilic cells with basally sited vesicular nuclei. These findings are compared with reports on heterogeneity within both gastric dysplasia and dysplasia in other areas of the gastrointestinal tract. A link is demonstrated between incomplete intestinal metaplasia, type II dysplasia and the more poorly differentiated cancers of intestinal type.