Background: Gastric cancer is the 3rd most common cause of death in men and the 5th common in women worldwide. Today, surgery is the only curative therapy. Currently available advanced imaging modalities can predict R0 resection in most patients, but it can only be detected with certainty in the perioperative period. Aim: To determine the role of serum CK18, MMP9, TIMP1 levels in predicting R0 resection in patients with gastric cancer. Methods: Fifty consecutive patients scheduled for curative surgery with gastric adenocarcinoma diagnosed between 2013-2015 were included. One ml of blood was taken from the patients to analyze CK18, MMP9 and TIMP1. Results: CK18, MMP9 and TIMP1 levels were positively correlated with pathological N and the stage (p