The invention relates to novel TNF family ligand trimer-containing antigen binding molecules comprising (a) a Fab domain capable of specific binding to a target cell antigen, (b) a Fc domain composed of a first and a second subunit capable of stable association, and (c) a first polypeptide comprising two ectodomains of a TNF ligand family member or fragments thereof that are connected to each other by a peptide linker and a second polypeptide comprising one ectodomain of said TNF ligand family member or a fragment thereof, wherein the first polypeptide is fused at its N-terminus to the C-terminus of one of the subunits of the Fc domain and wherein the second polypeptide is fused at its N-terminus to the C-terminus of the other subunit of the Fc domain.
