The serum level determination of tumor markers in gastric cancer, more than other neoplasia, presents, many difficulties for the impossibility to identify specific molecules released during neoplastic growth. In this research the authors report their experience on the preoperative determination of two tumor markers diffusely used in gastrointestinal neoplasia: CEA and CA19-9. The study has been done in order to establish relations between the expression of markers and some considered variables. The values have been studied on 113 patients. A total of 24% sensibility was reported for CEA while 48% for CA19-9 applying cut-off levels of 10 mg/ml and 37 U/ml respectively. The results have shown a better sensibility of CA19-9 with a statistical significance between the expression of this marker and stage of disease (from 21% to 66%), lymph nodal involvement (from 31% to 59%), histologic grading (from 39% to 48%) and surgical purpose (from 37% to 78%) (p < 0.001).