Gastric cancer is the most common malignant neoplasm among Koreans, and the pathologists's daily diagnostic competency on gastric cancer at any hospital setting plays a critical implication not only in the quality of clinical service but also to the determination of patient's prognosis. Thus, adoption of a unified assessment system based on comprehensive understanding of pathologic features together with their active participation has been crucially demanded. Nevertheless, a considerable difference in handling procedures and diagnostic approach on gastric cancer among institutions apparently resulted in an extreme difficulty in exchange of clinicopathologic informations and in the nationwide survey. It is, therefore, essential and be the first step to develop a practical but scientific and reproducible classification of gastric cancer with its diverse gross and histologic findings. Based on the following basic principles, the Subcommittee on Gastric Cancer under the Gastrointestinal Study Group of the Korean Society of Pathologists has been requested to develop the guidelines of future pathologic study of gastric cancer to meet the above needs and be efficiently used with ease among the society members. 1) The prerequisite for pathologic classification of gastric cancer starts with consistency in handling of the resected stomach before its further examination. Thus, the guideline shall limits its scope only with the minimum agreement. 2) The classification should be simple and practical so that all pathologists can use with ease and with high reproducibility. 3) All the gross and microscopic findings which have been considered to be the prognosis-related factors should be included in every pathologic procedures to help future information exchange among pathologists and clinicians and to provide a meaningful role in determination of patient's prognosis. 4) The classification should be interchangeable and stand with compatibility among WHO and other internationally accepted classifications. 5) The guideline accepts in part the staging system of American Joint Commitee on Cancer, classification of early gastric cancer proposed by the Japanese Society of Gastrointestinal Endoscopy, and the General Rules of Stomach Cancer Study by Japanese Research Society of Gastric Cancer, until otherwise developed and accepted by the Korean Society of Pathologists. 6) The guideline should not interfere with each institution-based special study. The details of the handling procedures of the resected stomach cancer, its gross and histologic classifications and descriptive methods of prognostic factors are supplemented with illustrations.