The separation of interfering ions in the quinalizarin colorimetric determination of gallium by means of anion exchanger (Ⅰonaustauscher Ⅲ, Cl-form, strongly basic anion exchanger) was examined. Procedures for the determination of gallium in bauxite,alunite, galena and sphalerite have been devised. The results found are very close to those obtained with the ether extraction method.