We studied the influence of the morphological mode of tumor invasion in muscularis propria (pm) layer, in 177 patients who received resection for colorectal carcinoma that invaded beyond the pm layer. Tapering Index (TI = A/B) defined from the ratio between the length of tumor invasion on upper pm layer (A) and that on lower pm layer (B), TI value was significantly lower in cases with hematogenous metastasis than that in cases without hematogenous metastasis. Cases in which TI values were under 1.3 in colon cancer and 1.9 in rectal cancer had higher possibility of synchronous or metachronous hematogenous metastasis and poorer prognosis. Therefore, we suspected that TI value would be an important factor in prediction of hematogenous metastasis.