With the aid of an image quantifier, the nuclear area in Feulgen-stained sections from 29 gastric adenomas and 8 hyperplastic gastric polyps were recorded. In each specimen, the nuclear area and the total mucosal area were measured in three consecutive fields of (1) the lesion and (2) its adjacent normal gastric mucosa. The results, expressed as the percentage of the nuclear area to the total mucosal area, showed significantly higher (P less than .001) values in gastric adenomas than in hyperplastic gastric polyps. The highest mean of the difference between the nuclear values was found in gastric adenomas with invasive growth. The method reported herein appears to be useful for making the differential diagnosis between neoplastic and nonneoplastic polyps arising in the gastric mucosa.