Abstract: A method for determining trace silver in rocks by NAA has been developed.After pile neutron activation, the sample is dissolved in mixed acid. The tracesilver is selectively separated by means of thiourea--type chelating resin. The resinadsorbed ~(110m)Ag is counted directly on Ge (Li) γ--spectrometry. The content ofsilver in sample is determined by the relative method. The chemical yield of~(110)mAg through the complete procedure is 95%. Several kinds of rock samples areanalyzed, with contents of silver in the range of 10~(-7)--10~(-8)g/g. The standard reference materials are analyzed simultaneously. The resultsagree well with the available value of certification. The precision of the methodis±10%.