In the title compound, C9H7N3O3S, the nitro and thiazolidinone moieties are inclined with respect to the aromatic ring at dihedral angles of 9.57 (16) and 78.42 (4)°, respectively. In the crystal, N—H...O hydrogen bonding connects the molecules along the c and a axes to form a two-dimensional polymeric network. A weak S...O interaction [3.2443 (11) Å] and phenyl ring to phenyl ring off-set π...π stacking [with centroid–centroid separation of 3.6890 (7) Å and ring slippage of 1.479 Å] link the polymeric chains along the b and a axes, respectively.