In the title compound, C(11)H(8)Cl(2)N(2)O, the benzene and pyridazine rings are tilted by 8.6 (1)° relative to each other. In the crystal, pairs of inter-molecular N-H⋯O hydrogen bonds form centrosymmetric dimers. π-π contacts with centroid-centroid distances of 3.698 (2) and 3.751 (1) Å and halogen-halogen inter-actions [3.379 (1) Å] also stabilize the structure.