A method for the spectrophotometric determination of cobalt (II) by complexation with di-2-pyridyl ketone benzoylhydrazone (DPKBH) in 50% (v/v) ethanolic solution is described. Cobalt (II) forms a 1:2 complex with DPKBH. The complex has maximum absorbance at 370 nm. Beer's law is obeyed over the range 0.1 – 2.8 μg.ml−1. The effect of pH, effect of excess reagent, stability of the complex and the tolerance limit of many metal ions have been reported. The method is applied to the determination of cobalt in different alloys containing other metals ions.