This paper reviews the gross morphology, histologic classification, location, and modes of spread of gastric cancer. On the basis of gross appearance, we have classified gastric carcinoma into 4 types: (a) superficial spreading (6% of cases), (b) polypoid (11% of cases), (c) ulcerated (45% of cases), and (d) diffuse infiltrating (38% of cases). Our histologic classification includes 4 categories: (a) adenocarcinoma (70% of cases), (b) round cell carcinoma, (c) mucinous carcinoma, and (d) rare forms of carcinoma (squamous, adenoacanthoma, carcinosarcoma, collision tumor, ductogenic carcinoma). These main histologie categories are subdivided according to the degree of differentiation of each tumor. From 81 to 86% of gastric cancers arise in the pyloric region. Multifocal origin of stomach cancers occurs in about 10% of cases. The prognosis of gastric cancer depends on the extent of spread at the time of treatment. Intramural propagation beyond the grossly apparent margins is common, and extension into the duodenum and esophagus from lesions in the pylorus and cardia regularly occurs. Approximately 50% of gastric cancers infiltrate neighboring organs. Metastases to regional lymph nodes, particularly in the lesser curvature drainage area, occur in over half of the cases. Blood‐borne spread, to the liver and beyond, and peritoneal seeding are common.