In the mononuclear title salt, [Ag(C3H8N2S)(C18H15P)3](CH3COO), the Ag(I) ion exhibits a distorted tetra-hedral coordination sphere defined by three P atoms from three tri-phenyl-phosphane ligands and one S atom from a 1,3-di--methyl-thio-urea ligand. In the crystal, the acetate anion is linked with the complex cation via duplex N-H⋯O hydrogen bonds [graph-set motif R (2) 2(8)].