Galectin-3 is a specific soluble lectin of the beta-galactoside family. It plays an important role in cell adherence, proliferation, and differentiation. It has also been shown that galectin-3 expression correlates with tumor progression in several types of cancers. We investigated the involvement of galectin-3 in colorectal cancer development. We performed a comparative immunohistochemical analysis of galectin-3 expression in term of intensity and distribution in normal mucosa, in primary tumor and in metastasis from 200 patients with colorectal cancer selected among 325 cases. We also compared the galectin-3 staining according to the histological subtype (mucinous vs non mucinous), tumoral differentiation and stage of tumor. We showed a strong and diffuse positive staining of galectin-3 in both adjacent and distanced normal mucosa, in well differentiated adenocarcinoma and in metastasis. However, we note a progressive decrease of galectin-3 staining according to the decreasing degree of tumoral differentiation. We also observed a loss of this protein in adenocarcinoma with mucinous component < 50%, where the positive staining was limited only to the well differentiated areas of tumor. These data suggest that galectin-3 play an important role in colorectal cancer progression concerning the non mucinous carcinoma and can be used as a prognostic factor to predict poor outcome of patients. In mucinous subtype, galectin-3 might be implicated in one or many step of its genesis perhaps through the control of cellular adhesion and interaction with mucin produced. Adenocarcinoma with mucinous component <50% would be integrate to mucinous carcinoma, not to non mucinous ones. These investigations could open perspectives for therapeutic means targeted to improve the prognosis of this neoplasm.