Nickel(II) complex of [NiL2](ClO4)2, where L is an unsymmetrical tridentate ligand of 2-(2-aminoethyl)imino-3-butanone oximehas been synthesized by a template condensation reaction. The complex was characterized on the basis of microanalytical, spectroscopic, and other physicochemical properties. X-ray diffraction study of the complex reveals nickel(II) center in a distorted octahedral environment through two amine nitrogen donors, two imine donors, and two nitrogen atoms of the oxime moieties of the ligand. The antibacterial activity of the complex has been tested against Gram(+) and Gram(-) bacteria. The results of the antibacterial screening indicated that the complex is effective against bacterial growth retardation activity to some extent and its effectiveness is higher forGram(+) bacteria