The title mol-ecule, C(12)H(10)N(2)O(5), is non-planar with dihedral angles of 89.08 (7) and 83.21 (7)° between the phthalimide and acetamide mean planes, and the acetamide and acetic acid mean planes, respectively. In the crystal, symmetry-related mol-ecules are linked via N-H⋯O and O-H⋯O hydrogen bonds, forming an undulating two-dimensional network. There are also a number of weak C-H⋯O inter-actions, leading to the formation of a three-dimensional arrangement.