A new extractive-spectrophotometric method for determination of copper(II) with 4-(p-nitrophenylazo)-2-amino-3-pyridinol is proposed. The established stoichiometry and extraction constant are 2:1 ligand:metal and -1.55, respectively. The molar absorptivity of the complex is 5.19 × 104 liters mol-1 cm-1 at 560 nm and Sandell's sensitivity is 1.2 ng cm-2. The best conditions for determination and effect of other ions are studied. The method proposed is applied in the determination of copper in whisky, liver of fish, and seawater. © 1985.