One hundred forty-eight cases of colon carcinoma were subjected to further pathologic study. Survival was correlated with stage and grade of the tumor and with the number of involved lymph nodes. In addition, cases were assessed as to the extent of local chronic inflammatory reaction about the lesion and the degree of sinus histiocytosis in draining lymph nodes. A correlation was possible between grading, staging, extent of lymph node involvement, and survival. A substantial difference in five-year survival was shown when local inflammatory reaction was present and when sinus histiocytosis was observed. The presence of both of these factors further improved survival. An adequate evaluation of these factors, both individually and in combination, should improve our ability to assess prognosis in colon cancer.