AbstractHuman monoclonal antibodies are extremely difficult to obtain by hybridoma technology. As an alternative, ‘human‐like’ antibodies have been produced by recombinant DNA technology. The first such engineered antibodies consisted of chimaeric proteins, in which murine variable regions were linked to human constant regions. More recently ‘human’ antibodies have been ‘reshaped’ by transplanting the binding site of a murine antibody into a human antibody. Further‐more antibodies have been dissected into groups of domains (Fab's, Fc's) and for example, Fab's have been joined to enzymes resulting in antibody‐enzyme chimaeras. In addition to their potential clinical applications, engineered antibodies will prove invaluable in studies of structure/function relationships of variable and