Embodiments of the present invention utilize a more efficient CDR grafting technique to generate humanized versions of the T84.66 antibody. The technique used to generate these antibodies utilizes crystallographic structural data to select an immunoglobulin framework having maximum structural overlap with a non-human donor molecule. This technique was used to develop humanized T84.66 antibodies exhibiting in vitro binding affinity and specificity for carcinoembryonic antigen (CEA) nearly identical to that of T84.66 and the ability to specifically target tumors expressing CEA in vivo.