The title compound, C14H11N3O4, was prepared by the reaction of 3-nitrobenzohydrazide with 3-hydroxybenzaldehyde. The molecule adopts an E configuration about the C=N bond. The dihedral angle between the two benzene rings is 32.3 (2)°. In the crystal, the molecules are linked through intermolecular N—H...O, O—H...N, and O—H...O hydrogen bonds, forming chains in the a-axis direction.