Serum pepsinogen I (PGI) levels were measured in 192 gastric carcinoma (GC) patients and 70 controls. Among GC patients serum PGI levels were not influenced by the following variables: age, sex, smoking, Borrmann's or Lauren's classification, tumor size, cellular differentiation, and layer of invasion. The mean serum PGI levels of tumors restricted to the body, antrum, or involving both areas were 64.8 +/- 37.6 ng/ml, 76.0 +/- 47.0 ng/ml, and 51.1 +/- 25.5 ng/ml, respectively (P < 0.005). Odds ratios of GC patients from the quartile of 262 serum PGI levels in the limits > or = 100 ng/ml, 70-99.9 ng/ml, 45-69.9 ng/ml, and < 45 ng/ml were 1.00, 0.76, 3.44, and 37.1, respectively (P < 0.001). The lower serum PGI levels of Chinese GC patients seem to be related to disease location rather than other characters of the tumor.