Background/Aims: It has been demonstrated that several solid tumors are angiogenesis-dependent in their growth and metastasis. The purpose of the study is to investigate the correlation between tumor angiogenic activity and clinicopathologic factors, and to evaluate the availability of angio- genic activity as an independent prognostic factor in patients with advanced gastric carcinoma. Methods: One hundred and fifty-seven patients with advanced gastric carcinoma who underwent curative radical surgery in Yonsei University, Yong-Dong Severance Hospital from Jan. 1986 through Dec. 1989 were studied retrospectively. The most representative section having the invasive component of the tumor by hematoxylin and eosin stain were stained with monoclonal antibody against factor VIII-related antigen. Results: Of 157 patients, the mean survival duration was 55.6 months and the mean microvessel count was 78.1/field(200 times of magnification). The microvessel count increased with AJCC tumor stage(p=0.0165) by univariate analysis. Clinico- pathologic factors independently related to microvessel count were AJCC tumor stage(p=0.0041) and the location of tumor(p=0.0429), but clinicopathologic factors including histologic type, gross morphology, size, age and sex were not independently related to microvessel count. T'he prognosis of the group of which microvessel count more than 78/field was significantly worse than that of the group for which microvessel count was 78/field or less(p=0.0232). Clinicopathologic factors independently related to the survival were AJCC tumor stage(Ib vs. IIIb, p=0.0017) and microves- sel count(<78 vs. 78, p=0.0281) but presence of chemotherapy and other clinicopathologic factors were not independently related to the survival. Conclusions: The number of microvessel showed positive correlation with tumor stages in patients with advanced gastric carcinoma who underwent curative radical surgery. The number of rnicrovessel may be an independent available prognostic factor. (Korean J Gastroenterol 1996; 28:502 - 512)