[en] The determination technique of zirconium (from 0.02 up to 0.2%) and hafnium (up to approximately 1%) in the ZhS6U type nickel base alloys is suggested. The feature of the hafnium complex with arsenazo 3 in the 4 n hydrochloric acid is used to reduce sharply light absorption, whereas that of zirconium complex does not change. The conclusion is made of the possibility to determine zirconium with arsenazo 3 on the background of hafnium. Opacity of solutions is measured at spectrophotometer. Samples of nickel base alloys containing 1% Hf and 0.04% Zr are analyzed