The development of colorectal carcinoma is a sequential process associated to chromosomic instability and to mutations of oncogenes as KRAS, of tumor suppressor gene as p53, or loss of APC, leading to uncontrolled cell proliferation and transformation. Cyclooxygenase 2 (COX-2) is an inducible enzyme, whose expression can be influenced by proinflammatory and mitogenic stimuli such as those caused by cytokines and growth factors, has been proposed as an enzyme regulating cell proliferation, and therefore carcinogenesis, which can play an important role in the development of metaplastic and dysplastic tissues, as well as in the development and progression of cancer as colorectal tumors. Different techniques have been used to identify COX-2 expression in colorectal neoplasms, one of the most widely used is the immunohistochemistry, whose results have generally shown higher staining in tumor tissue compared to normal colorectal mucosa. Most published studies have suggested that the common overexpression of COX-2 in colorectal carcinoma could be used as a biomarker for this neoplasm.