In the title compound, C10H9ClN2O4, the oxazolidinone ring adopts a near-planar conformation, with mean and maximum deviations of 0.0204 (8) and 0.0328 (8) Å, respectively. The nitro group is twisted slightly from the plane of the benzene ring, making a dihedral angle of 6.79 (3)°. The dihedral angle between the mean oxazolidinone plane and the benzene ring is 56.21 (3)°. In the crystal, N—H⋯O hydrogen bonds and N—O⋯π interactions [O⋯centroid distances = 3.478 (1) and 3.238 (1) Å] dominate the packing, forming infinite zigzag chains along the b-axis direction. Neighbouring chains are linked together through C—H⋯O and C—H⋯Cl interactions. The absolute configuration of the two stereogenic centres was determined using the anomalous dispersion of the Cl atom.