The tetraphenylphosphonium salt of tetrakis(1-methyl-1,2,3,4-tetrazole-5-thiolato)aurate(III) crystallizes as an H2O hemisolvate, (C24H20P)[Au(C2H3N4S)(4)]. 0.5H(2)O, in the monoclinic C2/c space group, with the Au atom situated on an inversion centre. The tetrazole rings are arranged almost orthogonally with respect to the square coordination sphere. Au-S-C angles of 106.2(1) and 107.1(1)degrees were found.