An accurate and reliable method has been developed for the estimation of radiocesium in urine. Initially cesium is adsorbed on ammonium phosphomolybdaste (AMP) precipitate and separated by ion exchange from other contaminants. Cesium thus separated is estimated as cesium chlorostannate, Cs2SnCl6, from a 50 (v/v)% solution of concentrated HCl in ethyl alcohol. While the results are in good agreement with the values obtained by γ-spectrometry using a Marinelli beaker in its range of applicability, the present method has a much lower detection limit. It is observed that the method has significant advantages over the methods available with respect to analysis time, accuracy and detection limits.