The title compound, trans-[PtCl(CH3){As(C6H4CH3)(3)}(2)]. is one of the few his tertiary arsine complexes of platinum(II). The complex exhibits square-planar geometry with the two arsine ligands in a non-linear trans orientation with an Asl-Pt-As2 bond angle of 175.66 (4)degrees. The large trans influence of the methyl substituent is manifested in the long Pt-Cl bond distance of 2.397 (3) Angstrom.