A study was conducted to understand the adsorption of N-hydrocinnamoyl-N-phenylhydroxyl- amine (HCNPHA) on the surfaces of various pure minerals: sphalerite, pyrite, galena, chalcopyrite and quartz. HCNPHA is a member of the N-arylhydroxamic acids that are good base metal mineral collectors and HCNPHA gave the most promising results within the group.In this work, equilibrium studies were conducted at pH 9 and 10, using pure minerals and some microflotation studies were also undertaken. Chemisorption appears to be the most probable mechanism of adsorption on metal sulphide minerals....