A radiochemical procedure is described for the sensitive determination of89Sr and90Sr activity concentrations in soil and sediment samples. After leaching the sample with hydrochloric acid, Sr is separated from most of the soluble matrix constituents and Ca by solvent extraction using dicylclohexano-18-crown-6 in trichloromethane. After backextraction with a EDTA-solution (ethylene diamine tetra acetate), Sr is purified by several precipitation steps from traces of matrix constituents and radionuclides which might interfere the beta measurements of89Sr,90Sr and90Y. The detection limits are about 0.2 Bq/kg and 0.4 Bq/kg for90Sr and89Sr respectively. The procedure can be applied to all kind of environmental samples with small modifications of the sample preparation steps prior to analysis.