The structure of the cis-dichlorotetrakis (dimethyl sulfoxide) ruthenium(II) have been studied by means of single-crystal X-ray diffraction. The data are described in orthorhombic unit cell with space group Pccn (No. 56) at 295 K, a = 28.478 (4) Å, b = 10.900 (6) Å, c = 11.697(13) Å, and V = 3631 (4) Å3, Z = 8. The crystal structure of the title compound comprises a nearly octahedral configuration with a Ru-O bond distance of, 2.151 Å, and the average values of, 2.269 Å and 2.421 Å for Ru-S and Ru-Cl, respectively.