A simple and accurate technique is described for the standardization of different metallic carbonates tagged with C14based on the liberation of radioactive carbon dioxide by the action of concentrated sulphuric acid followed by the continuous monitoring of the carbon dioxide in the stream of carrier gas by a flow monitoring Geiger counter. Results showed that the technique could be applied successfully and reproducibility for samples with specific activities as low as fractions of a millimicrocurie per milligram labelled carbonate and that it is much more reliable than other techniques usually applied.