Nuclear DNA content was microspectrophotometrically measured in 120 gastric cancer patients to assess the predominance of a particular DNA distribution pattern in gastric cancer with biologically high malignancy, such as the marked tendency for severe vessel invasion and remote metastasis, and for early recurrence after curative surgery. DNA distribution patterns were grouped into low and high ploidies, and the correlation between the DNA ploidy pattern and histopathologic, biologic findings was evaluated. The incidence of high DNA ploidy tended to be increased as the histological stage and level of infiltration progressed. On the other hand, the incidence of high DNA ploidy was higher in dead cases of early recurrence among cases of the same histological stage, or where vessel invasion and remote metastasis were severe among cases of the same depth of invasion. Therefore, we consider that the DNA distribution pattern well reflects the malignancy of gastric cancer.