Abstract Background: Carcinoembryonic antigen (CEA) has been widely accepted as a tumor marker useful in the diagnosis and management of colorectal cancer. When CEA levels are positive in gastric cancer patients, they could be useful prognostic indicators. However, the value of CEA as a tumor marker for gastric cancer remains a matter of controversy. Study Design: We measured preoperative serum CEA levels in 196 patients with resectable gastric cancer between May 1986 and April 1996 and then evaluated the correlation between serum CEA levels, clinicopathologic features, and prognostic information. Results: Serum levels of CEA were above the normal range in 29 of 196 (14.8%) surgically resected patients (range, 5.2–570 ng/mL). Among 100 early gastric cancers confined to the submucosal layer, only 7 patients (7.0%) had positive CEA levels, but among 96 advanced cancers, 22 patients (22.9%) had high CEA levels. The CEA positive patients had more macroscopically infiltrative tumors, a more prominent serosal invasion, more frequent lymph nodes involvement, and a more advanced stage than did the CEA negative patients. The 3- and 5-year cumulative disease-specific survival rates of patients positive for serum CEA were 39.6% and 31.7%, respectively; these rates for patients negative for CEA were 83.0% and 77.3%, respectively (p < 0.0001 for comparison of survival curves). In various clinicopathologic parameters, nine parameters (tumor size, macroscopic type, type and time of operation, Laurén classification, depth of invasion, lymph node involvement, CEA, α-fetoprotein [AFP], and carbohydrate antigen [CA] 19-9) showed statistically significant differences in the cumulative survival rates. Of these nine parameters, independent prognostic factors by multivariate analysis were depth of invasion (T1, 2 versus T3, 4, p < 0.0001), serum CEA levels (negative versus positive, p = 0.0003), and lymph node metastasis (negative versus positive, p = 0.0005). Conclusions: Preoperative serum CEA levels provide a predictive value in determining tumor stage and prognostic information for patients with potentially resectable gastric cancer during the preoperative period.