Spread of tumor cells in linitis plastica type of gastric carcinoma was studied in relation to features of tumor cell aggregation which were classified into two types; free-cell type and small nest type. Free-cell type was accompanied by a larger amount of fibrous stroma in submucosal layers than in small nest type. In the gastric wall lymphatics and regional lymph nodes, small nest type was more prominent than the free-cell type. Lymphatic permeation was noted predominantly in the submucosa. In the mucosa, both free-cell and small nest types were frequently present. In carcinoma with free-cell type predominance, diffuse infiltration with infrequent lymphogenous spread was noted, while in carcinoma with small nest type predominance, spread via the lymphogenous route was observed more frequently. The mode of cancer spread in this type of carcinoma appeared to be affected by the type of tumor cell aggregation dominant in the mucosa.