The invention relates to a method of preparing heteromultimeric polypeptides such as bispecific antibodies, bispecific immunoadhesins and
antibody-immunoadhesin chimeras. The invention also relates to the heteromultimers prepared using the method. Generally, the method provides a multispecific
antibody having a common light chain associated with each heteromeric polypeptide having an
antibody binding domain. Additionally the method further involves introducing into the multispecific antibody a specific and complementary interaction at the interface of a first polypeptide and the interface of a second polypeptide, so as to promote heteromultimer formation and hinder homomultimer formation; and / or a
free thiol-containing residue at the interface of a first polypeptide and a corresponding
free thiol-containing residue in the interface of a second polypeptide, such that a non-naturally occurring
disulfide bond is formed between the first and second polypeptide. The method allows for the enhanced formation of the desired heteromultimer relative to undesired heteromultimers and homomultimers.