In the title triangulo-triruthenium compound, [Ru3(C21H21As)(C25H22P2)(CO)9], the bis(diphenylphosphino)methane ligand bridges an Ru—Ru bond and the monodentate arsine ligand bonds to the third Ru atom. Both the phosphine and arsine ligands are equatorial with respect to the Ru3 triangle. Additionally, each Ru atom carries one equatorial and two axial terminal carbonyl ligands. The three arsine-substituted phenyl rings make dihedral angles of 87.36 (10), 81.96 (10) and 73.37 (11)° with each other. The dihedral angles between the two phenyl rings are 88.08 (12) and 80.15 (10)° for the two diphenylphosphino groups. In the crystal packing, the molecules are linked together as dimers via intermolecular C—H⋯O hydrogen bonds. These dimers are stacked down b axis. Intermolecular C—H⋯π and π–π interactions [centroid–centroid distance = 3.6383 (13) Å] further stabilize the crystal structure.