Flow cytometric (FCM) DNA studies were performed on cell suspensions obtained by endoscopic biopsy in 73 patients with gastric cancer and in 61 patients with gastric remnant. In cancer, DNA aneuploidies were detected in 49 tumors (67.1 %), including 51.7% (15/29) of early gastric cancers and 77.3% (34/44) of advanced gastric cancers. Nuclear DNA content of biopsy materials had a significant correlation with that of surgically obtained ones, providing the estimation of the original ploidy pattern and DNA index (p < 0.01). The serosal invasion, lymph node metastasis, lymphatic invasion, and vascular invasion of the DNA aneuploidy were significantly higher than those of the DNA diploidy (p < 0.05). In patients with gastric remnant, 9 biopsy specimens in the anastomotic site showed DNA aneuploidy (13.9%). The DNA measurement of the endoscopically obtained specimens may provide additional preoperative information and help to identify biologic variables.