The title compound, [PtCl2(C21H33P)2]·C3H6O, crystallizes with an accompanying acetone solvent mol­ecule. The metal atom shows a distorted square-planar coordination environment, with a P—Pt—P angle of 172.41 (3)° as the most prominent feature. Both isopropyl fragments were treated as disordered over two conformations with occupancy ratios of 0.55 (2):0.45 (2) and 0.58 (2):0.42 (2). The solvent mol­ecule was also disordered over two orientations in a 1:1 ratio. The crystal studied was a non-merohedral twin with a twin component of 32.4%.