Sentinel lymph node (SLN) mapping has been found to be highly effective in correctly predicting the nodal status for melanoma and for breast cancer. This study shows that SLN mapping also is highly successful in colorectal cancer, posing minimal cost and no complications. The procedure accurately determines the presence or absence of nodal micrometastasis in more than 96% of cases. This article reviews the in vivo and ex vivo techniques for SLN mapping in colorectal cancer, along with its limitations and pitfalls.