In the title compound, [Ni(C(8)H(7)O(3))(C(10)H(8)N(2))]ClO(4), the Ni(II) atom is in a slightly distorted square-planar coordination by two N atoms from the 2,2'-bipyridine (bipy) ligand and two O atoms from the deprotonated 2-formyl-6-methoxy-phenolate (mbd) ligand. The bipy ligand is nearly coplanar with the Ni(II) square plane, the Ni atom being only 0.042 (2) Å from the mean plane, whereas the benzaldehyde plane is folded with respect to the square plane, making a dihedral angle of 19.17 (8)°. One of the O atoms of the perchlorate anion is involved in a weak inter-action with the Ni atom, with an Ni-O distance of 2.5732 (18) Å. The packing is stabilized by weak C-H⋯O inter-actions.