In the molecule of the title compound, C12H11ClN4O4, the pyrazole ring is coplanar with the amino and ethoxycarbonyl groups within 0.026 (2) and 0.105 (2) Å, respectively. The C
6 ring of the 4-chloro-2-nitrophenyl group is twisted by 53.58 (4)° relative to the plane of the pyrazole ring. The planar structure of the pyrazole ring is stabilized by an intramolecular N—H⋯O hydrogen bond between its substituents. Neighbouring molecules are linked through intermolecular N—H⋯N and N—H⋯O hydrogen bonds, giving rise to one-dimensional tapes along the b axis. Molecules in the chain are linked to those of an adjacent chain through weak C—H⋯O interactions, forming a three-dimensional network.