A method for the simultaneous extraction and concentration of cadmium and zinc from soil extracts is described and evaluated. The procedure, using dithizone-carbon tetrachloride extraction at pH 4.5, is simple and reliable, giving an essentially quantitative recovery of cadmium and zinc added to calcium chloride extracts of several contrasting soils. The method was used to evaluate the effect of long-term superphosphate fertiliser addition on the cadmium and zinc contents of soil.