CA 72-4 serum marker has been shown to be one of the most specific and sensitive markers for monitoring gastric cancer. In the present study we evaluated the correlation between CA 72-4, CA 19-9 and CEA serum levels, and tumor size and lymph node involvement in gastric carcinoma patients. One-hundred sixty-one patients with primary or recurrent gastric carcinoma were studied. Elevated CA 72-4, CA 19-9, and CEA serum levels were found in 42.2%, 32.3% and 24.2%, respectively. As previously shown, the combination of CA 72-4 and CA 19-9 increased positive samples to 56.5%, while the addition of CEA did not further improve this percentage. Unlike what has been previously published, none of the markers showed a significant correlation with serosal involvement. In fact, elevated serum levels were observed for the three markers in a very low percentage of cases either in T1-T2N0 or T3-T4N0 patients. In contrast, CA 72-4 showed a highly significant correlation with lymph node involvement: T1-T4N0 patients had positive CA 72-4 levels in 5 out of 37 (13.5%), while T1-T4N1 in 12 out of 32 (37.5%), and T1-T4N2 in 20 out of 40 (50%) (p < 0.003). CA 19-9 and CEA serum levels were not significantly correlated. Since the presence of lymph node metastases is considered a negative prognostic factor, these results suggest that the measurement of CA 72-4 serum levels may be an important parameter in the diagnosis and clinical follow-up of patients with gastric carcinoma.