PURPOSE: The evaluation of tumor recurrence or metastasis in postgastrectomy cancer patients usually depends on a serum tumor marker test or radiologic study, but in both cases, accuracy is difficult to determine. The purpose of this study was to evaluate the relationship between abdominal CT and serum tumor markers. MATERIALS AND METHODS: In 337 cases involving 226 patients who had undergone curative surgery for gastric cancer, we compared serum tumor markers and CT for the evaluation of metastasis. Among these 337 cases, CEA level was measured in 317, CA 19-9 level in 166, and both of these in 146. The cutoff level for serum carcinoembryonic antigen (CEA) and CA19-9 were 10 ng/ml and 33 U/ml, respectively. RESULTS: CEA level was elevated in 59 of 317 cases (18.6 %) and that of CA 19-9 in 58 of 166 (34.9 %). Slightly higher overall senstivity and specificity was observed for CEA than for CA 19-9 (72.9 % vs 67.2 %, 83.3 % vs 70.4 %, respectively). Among the total of 337 cases, liver or lymph node metastases were detected in 91 cases (27.0 %) on CT. Negative predictive value was significantly higher in CEA than in CA 19-9 (93.1 % vs 80 %, respectively) (p < 0.01), but positive predictive value was lower (50 % vs 54.9 %, respectively). On CT scan, there was a significant relationship between serum tumor marker level and hepatic and nodal metastasis ; specificity and positivity of serum tumor markers were both higher than sensitivity and negativity. CONCLUSION: Follow-up CT less useful when tumor markers levels are not elevated, but when these are elevated in postgastrectomy cancer patients, meticulous radiologic evaluation is necessary for the early detection of residual or recurrent tumors.