N'-(4-Hydroxy-benzyl-idene)aceto-hydrazide monohydrate.

In the title compound, C(9)H(10)N(2)O(2)·H(2)O, the mol-ecular skeleton of the acetohydrazide mol-ecule is nearly planar [within 0.014 (1) Å]. The mol-ecule adopts a trans configuration with respect to the C=N bond, while the side chain is slightly twisted away from the attached ring, forming a dihedral angle of 9.975 (8)°. The crystal packing exhibits a three-dimensional network composed from alternating acetohydrazide mol-ecules and uncoordinated water mol-ecules, which inter-act via N-H⋯O, O-H⋯O and O-H⋯N hydrogen bonds. A C-H⋯π inter-action is also present.