The complexation reaction of phenyl 2-pyridyl ketoxime with some transition and heavy metal ions Co2+, Ni2+, Zn2+, Pb2+, Fe2+, Fe3+, Cr3+ and La2+ has been studied potentiometrically. The reactions of phenyl(2-pyridyl)ketone oxime, with nickel(II) sulfate hexahydrate, in the absence of an external base, have been investigated.