The aim of the paper is to investigate significance of the endoscopic ultrasound (EUS) in diagnostic and staging of gastric lymphoma. Retrospective clinical study was conducted at the Clinic for Hematology and Clinic for Gastroenterology of the University Clinical Center of Sarajevo in the period of years 2002 to 2009. Patients (N = 40) with diagnosis of gastric lymphoma confirmed by pathohistological diagnosis were included in the study. Stage of the disease was determined based on EUS, proximal endoscopy, CT and ultrasound of abdomen, and classified according to the Ann Arbor classification. 39 patients had various types of non Hodgkin lymphoma and one patient had Hodgkin lymphoma. Based on morphological characteristics of gastric tumor visualized with EUS in 16 patients a gastric cancer was suspected. In 40% patients EUS finding was not confirmed by pathohistological finding. Compared both to CT and ultrasound of abdomen, EUS showed statistically significant higher frequency of establishing existence of infiltration (p < 0.001). In patients with primary gastric lymphoma EUS has more significant role in determination of stage of disease spread than for the diagnosis itself. Therefore EUS should be included into algorithm of patient diagnostic protocol when suspected to the malignant gastric disease.