Gastric cancer is the second leading couse of death from malignant disease in the world and is one of the most difficult malignancies concerning the treatment, primarily because in most cases it is diagnosed in late stages. Gastric cancer is one of the few malignancies for whom has been proven that the infectious agent plays an important etiologic role. Infection with H. Pylori causes chronic active gastritis, which may represent a risky step in the cascade of the development of gastric cancer. Epstein-Barr virus (EBV) has been detected in 2-16 % of gastric cancer in the world, but its role in carcinogenesis is not clearly established. The environmental, non-infectious etiological factors include the diet rich in salt, nitrates and low in antioxidants. Ooi et al. identified 3 oncogene patways that are deregulated in the majority of cases (>70 %) of gastric cancer: proliferation/stem cells, NF-kappaβ and Wnt/beta-catenin pathways. Their research suggests that the interaction of these processes may play an important role in guiding the progression of the disease and determining the survival rates. The choice of therapy requires pre-staging of malignant disease, most commonly using TNM-classification which plays an important role in the prognosis of the disease, too. There are more than few therapeutic modalities: surgery (curable and incurable resection, palliative surgery), adjuvant and neoadjuvant chemotherapy and radiotherapy and symptomatic treatment.