A spectrophotometry method for the determination of nickel (II) with nicotinohydroxamic acid (NHA) in the presence of Triton X-100 was studied at pH 9.0 using phosphate-borax buffer medium. Molar absorptivity of the sensitized complex was 1.37 × 104 L mol-1 cm-1 at 530 nm and adhered to Beer’s law in the concentration range 0.43-8.56 μg mL-1 of nickel (II). The molar composition of the sensitized complex was 1:2 (nickel-NHA). The possible interfering effects of various ions were studied. The method was used for the determination of nickel in tap water and alloy samples.