A simple and rapid procedure was developed for the quantitative flotation of nickel(II) from aqueous solutions. Hydrazone derivatives such as: 4-acetylpyridine-[N-(3-hydroxy-2-naphthoyl)]hydrazone (H(2)APHNH), thiophene-2-carboxaldehyde-[N-(3-hydroxy-2-naphthoyl)]hydrazone (H2THNH), salicylaldehyde-[N-(3-hydroxy-2-naphthoyl)]-hydrazone (H2SHNH), p-anisaldehyde-[N-(3-hydroxy-2-naphthoyl)]hydrazone (H-2-p-AHNH) and ethylacetoacetate-[N-(3-hydroxy-2-naphthoyl)]hydrazone (H2EHNH) have been used as organic collectors and oleic acid as surfactant. The different parameters, affecting the flotation process, namely, ligand and surfactant concentrations, foreign ions (which are normally present in fresh and saline waters), pH and temperature are examined. Nearly 100% of nickel ions are floated at a metal:ligand ratio of 1:2, pH similar to 7 and at a temperature similar to 25degreesC. The procedure is successfully applied to recover Ni(II) from some water samples. The flotation mechanism is suggested.