In the title mol-ecule, [Cu(C(8)H(7)O(3))(ClO(4))(C(12)H(8)N(2))], the Cu(II) ion is five-coordinated by two N atoms [Cu-N = 1.995 (3) and 2.022 (3) Å] from a 1,10-phenanthroline ligand, two O atoms [Cu-O = 1.908 (2) and 1.927 (2) Å] from an o-vanillin ligand and one O atom [Cu-O = 2.510 (3) Å] from a perchlorate anion in a distorted square-pyramidal geometry. Three O atoms of the perchlorate anion are rotationally disordered between two orientations, with occupancies of 0.525 (13) and 0.475 (13). In the crystal structure, two mol-ecules related by a centre of symmetry are paired in such a way that the phenolate O atom from one mol-ecule completes the distorted octa-hedral Cu coordination in another mol-ecule [Cu⋯O = 2.704 (2) Å].