Toxin moiety in immunotoxin (IT) plays an important role in cytotoxicity of target cells. We constructed a recombinant immunotoxin (RIT), which is composed of a recombinant lectin A chain from Korean mistletoe (AKM) and a single-chain Fv (scFv) of an anti-carcinoembryonic antigen (CEA) monoclonal antibody. This single-chain IT was expressed in E. coli, purified, and refolded as a soluble protein. The resulting recombinant protein displayed strong cytotoxicity against CEA-expressing cancer cells but only minimal cytotoxicity against non CEA-expressing cells. The present study, we suggest that AKM may be a potential toxin candidate for development of an IT.