The extent of stomach resection in gastric cancer depends on tumor size, tumor location, depth of invasion, and the histological allocation to intestinal or diffuse type according to Laurén. As the latter is based on preoperative findings we performed a retrospective histomorphological study to quantify the differences between biopsy-related and surgical specimen-related Laurén classification. Additionally the World Health Organization (WHO) classification of preoperative endoscopic biopsies and surgical specimens were compared. Preoperative biopsies and resected tumor specimens from 100 patients with primary gastric carcinoma were retrospectively classified according toLaurén and WHO. The reclassification was independently performed by three pathologists who were not aware of the previous diagnoses. In 74% the Laurén classification of pre- and postoperative specimens was identical, whereas 26% of the cases showed a disagreement. Out of 48 tumors with preoperative diagnosis of an intestinal type, 10 tumors (20.8%) exhibited a diffuse growth pattern in the gastrectomy specimens; and 16% of the cases showed a disagreement of the pre- and postoperative histopathological type according to the WHO classification. Preoperative biopsy-related and surgical specimen-related Laurén classification differ in about one-quarter of the cases. Mostly, the preoperative diagnosis of an intestinal tumor type must be corrected into a diffuse or mixed type according to Laurén. Since this may have consequences for the surgical strategy, the extent of surgical resection, rebiopsies, and reconfirmation of an intestinal type should be performed at least in those cases with any doubts of this classification.