Galectin-3 is an endogenous lectin that binds glycan epitopes of cell membrane and some extracellular glycoproteins such as integrins and laminin. Galectin-3 is involved in several biological activities including regulation of cellular cycle, modulation of adhesion and tumor progression and metastasis. 90K/Mac-2BP glycoprotein is also a serum galectin-3 ligand. 90K is able to modulate the immune reaction against tumors and viruses and its level increases in sera of several neoplastic diseases. In our study, we have evaluated levels of both glycoproteins in sera of non metastatic colon cancer patients. Interestingly, galectin-3 ranged higher in cancer patients than in controls (p<0.0001), particularly in more differentiated tumors (p<0.04). Moreover, 90K mean values ranged higher in right-side than in left-side colon cancer. In conclusion, serum galectin3 might represent a useful biomarker to evaluate colon cancer transformation and, together with its ligand 90K, could contribute to the characterization of colon cancer.