&NA;A number of investigators have examined the influence of vascular invasion by tumor in colon, rectal, and colorectal cancer. Some consider the presence of vascular invasion an unfavorable prognostic feature and propose treatment recommendations based on its presence. Vascular invasion has two distinct components: blood vessel invasion and lymphatic vessel invasion. The use of elastic tissue stains enhance both the detection of blood vessel invasion and its differentiation from lymphatic vessel invasion. Almost all series report an increased incidence of blood vessel invasion with increasing stage and grade. Although the influence of blood vessel invasion and lymphatic vessel invasion on patterns of failure is variable, both are associated with a decrease in survival; however, treatment recommendations based solely on the presence of blood vessel invasion or lymphatic vessel invasion should be made with caution.