In the title compound, C(13)H(11)ClN(2)O(3), the nine-membered bicycle includes an oxime group having the C=N group in an E configuration. The isoxazole ring is almost planar [r.m.s. deviation = 0.0056 Å]; the dihedral angle between the isoxazole and 4-chloro-phenyl ring is 75.60 (5)°. In the crystal, inter-molecular O-H⋯N(isoxazole) hydrogen bonds give rise to chains running along the b axis.