In the title compound, C15H17NO4S2, synthesized by addition of O-ethylxanthic acid potassium salt to a diastereomeric mixture of (4R)-3-(2-chloro-propano-yl)-4-phenyl-oxazolidin-2-one, the oxazolidinone ring has a twist conformation on the C-C bond. The phenyl ring is inclined to the mean plane of the oxazolidinone ring by 76.4 (3)°. In the chain the methine H atom is involved in a C-H⋯S and a C-H⋯O intra-molecular inter-action. In the crystal, mol-ecules are linked by C-H⋯π inter-actions, forming chains along [001]. The S configuration at the C atom to which the xanthate group is attached was determined by comparison to the known R configuration of the C atom to which the phenyl group is attached.