Abstract: A method for the determination of trace cadmium in rock and soil samples by graphite furnace atomic absorption spectrometry (GFAAS) was developed. The samples were decomposed by aqua regia perchloric acid, and trace cadmium in perchloric acid medium was then directly determined by GFAAS without any separation, pre-concentration and without any matrix modifier. The conditions for sample decomposition, temperature of ashing and atomization in GFAAS determination were optimized. The detection limit of the method for cadmium is 0.0066 μg/g with precision of less than 8.0%RSD (n=12). The method provides the advantages of simple operation, high efficiency, accuracy, and suitable for the determination of trace cadmium in bulk rock and soil samples.