This study was intended to evaluate the prognostic and diagnostic significance of carbonic anhydrase IX (CA IX) and soluble urokinase plasminogen activator receptor (suPAR) levels in gastric cancer patients. CA IX and suPAR were analyzed from serum and plasma samples of gastric cancer patients. Fifty patients and 34 controls were enrolled. CA IX and suPAR levels were statistically significantly higher in the patient group (patient; 182.5 +/- 212.4, control; 47.3 +/- 32, P = 0.0001 and patient; 5.74 +/- 5.3, control; 2.27 +/- 0.77, P = 0.0001, respectively). CA IX and suPAR levels were higher in metastatic subjects (metastatic; 227.1 +/- 273.5, non-metastatic; 147.4 +/- 144.1, P > 0.05). Prognosis was worse in the patient group with elevated suPAR. CA IX and especially suPAR are correlated with the presence and stage of the disease. High suPAR levels indicate a poorer prognosis in gastric cancer patients.