In the title compound, C12H13N3O2S, the oxazolidin ring displays an envelope conformation. The dihedral angle between the benzimidazole ring and the 1,3-oxazolidin-2-one mean plane is 69.85 (13)°. In the crystal, molecules are linked by intermolecular N—H⋯N hydrogen bonds, forming a chain parallel to the b axis
