Lectins represent a class of proteins that recognize and interact with the carbohydrate moieties on biological polymers. Analyzed here are the lectins that interact with the fucose, the terminal carbohydrate residue of secretory glycoconjugates and plasma membrane glycopolymers of eukaryotic cells. The ability to selectively bind the unique fucose containing determinants, referred to as fine carbohydrate specificity, makes these proteins valuable in experimental and clinical cancer research. This review analyzes the state-of-the-art and recent advances in chemistry, isolation and biomedical applications of fucose specific lectins, the proteins that bind the fucose residues of carbohydrate antigens. Emphasizing the role of fucose containing determinants in cancer progression, the authors focus on fucose specific lectins as the tools for laboratory diagnosis of major human malignancies including leukemia and carcinomas of the colon, stomach and breast. Studies of this class of proteins may be highly productive for both understanding the mechanisms of the disease and for rational design of lectin-based diagnostic and therapeutic reagents.