In 120 operated cases of gastric cancer, nine tumor makers (serum carcinoembryonic antigen (CEA), alpha-fetoprotein (AFP), carbohydrate antigen 19-9 (CA19-9), carbohydrate antigen 125 (CA125), tissue polypeptide antigen (TPA), serum beta 2-microglobulin (s-BMG), urine beta 2-microglobulin (mu-BMG), serum immunosuppressive acidic protein (IAP) and sialic acid (SA)) were determined before operation, to explore distribution patterns, positive rates, and relationships among these markers. And, we explored tumor markers which would be useful in preoperative assessment of the cancer stage and feasibility of radical treatment. The following results were obtained. 1. The distribution of all tumor markers was close to normal logarithmic distribution. 2. The positive rate was high in the order of IAP > TPA > CEA > CA19-9 >s-BMG > SA > u-BMG > CA125 > AFP. 3. Strong correlations were observed between IAP and SA, between CA125 and TPA. 4. The optimum combination of markers for diagnosis of the cancer stage was IAP + CA19-9 + CA125 and the optimum combination for assessment of the feasibility of radical treatment was IAP + CA125 + TPA.