The reaction of K 2 PtCl 4 with 3-amino-5-methyl-5-phenylhydantoin (amphh, L) and KI in aqueous ethanol yields dark violet crystals of a binuclear platinum(II) complex. The molecular structure of the complex was determined by single-crystal X-ray diffraction methods. The complex crystallizes in the triclinic space group P 1 with a ¼ 8.458 (3), b ¼ 11.016(2), c ¼ 16.249(3) (Å ), ¼ 94.630(14), ¼ 100.63(2), ¼ 108.55(4) and Z ¼ 2. The structure consists of [K 2 L 4 ] 2þ cations and [Pt 2 I 6 ] 2À anions bridged by K-I bonds to form quasione-dimensional chains along the b axis. Chains are linked by K þ Á Á Á (Ph) interactions and N-H Á Á Á O hydrogen bonds. The complex is compared with data for related structures.