A dimeric antigen-binding molecule consisting of a first and a second polypeptide chain, each of the first and the second polypeptide chains containing - a first domain V L A being a light chain variable domain specific for a first antigen A; - a second domain V H B being a heavy chain variable domain specific for a second antigen B; - a third domain V L B being a light chain variable domain specific for the second antigen B; and - a fourth domain V H A being a heavy chain variable domain specific for the first antigen A, wherein - V L A is linked with V H B by a first linker L1, V H B is linked with V L B by a second linker L2 and V L B is linked with V H A by a third linker L3; - the first first domain V L A and the fourth domain V H A is specific for CD3; - the second domain V H B and the third domain V L B is specific for a tumor cell; - said linkers L1, L2 and L3 consist of 4 to 12 amino acid residues; - said domains are arranged in each of said first and second polypeptide chains in the order V L A-V H B-V L B-V H A from the N-terminus to the C-terminus of said polypeptide chains, and - the first domain V L A of the first polypeptide chain is in association with the fourth domain V H A of the second polypeptide chain to form an antigen binding site specific for CD3; - the second domain V H B of the first polypeptide chain is in association with the third domain V L B of the second polypeptide chain to form an antigen binding site specific for the tumor cell; - the third domain V L B of the first polypeptide chain is in association with the second domain V H B of the second polypeptide chain to form an antigen binding site specific for the tumor cell; and - the fourth domain V H A of the first polypeptide chain is in association with the first domain V L A of the second polypeptide chain to form an antigen binding site specific for CD3. - a first domain V L A being a light chain variable domain specific for a first antigen A; - a second domain V H B being a heavy chain variable domain specific for a second antigen B; - a third domain V L B being a light chain variable domain specific for the second antigen B; and - a fourth domain V H A being a heavy chain variable domain specific for the first antigen A, - V L A is linked with V H B by a first linker L1, V H B is linked with V L B by a second linker L2 and V L B is linked with V H A by a third linker L3; - the first first domain V L A and the fourth domain V H A is specific for CD3; - the second domain V H B and the third domain V L B is specific for a tumor cell; - said linkers L1, L2 and L3 consist of 4 to 12 amino acid residues; - said domains are arranged in each of said first and second polypeptide chains in the order V L A-V H B-V L B-V H A from the N-terminus to the C-terminus of said polypeptide chains, and - the first domain V L A of the first polypeptide chain is in association with the fourth domain V H A of the second polypeptide chain to form an antigen binding site specific for CD3; - the second domain V H B of the first polypeptide chain is in association with the third domain V L B of the second polypeptide chain to form an antigen binding site specific for the tumor cell; - the third domain V L B of the first polypeptide chain is in association with the second domain V H B of the second polypeptide chain to form an antigen binding site specific for the tumor cell; and - the fourth domain V H A of the first polypeptide chain is in association with the first domain V L A of the second polypeptide chain to form an antigen binding site specific for CD3.