The neutral cluster [Au8Mo4(CO)20(PPh3)4] was synthesized in low yield from [AuCl(PPh3)] and [Mo2(CO)10]2- in acetonitrile at room temperature. The cluster was characterized by X-ray analysis, IR, and 31P NMR spectroscopy. Its solid-state structure consists of four Au(3)Mo tetrahedral units, fused by four Au atoms in a ring. The average bond lengths are Au-Au 2.77 Angstrom and Mo-Au 2.93 Angstrom. The internal angles of the planar square ring are very close to 90 degrees.