[en] A simple and efficient method has been developed to preconcentrate natural protactinium from large quantity of monazite (5-10 g) and thorium concentrates (5-100 g), obtained from thorium plant stream on Dowex 1X8 in acid medium. Gamma-spectrometry, a powerful determination technique, has been used for quantitative determination of protactinium and uranium. Various parameters like sample preparation, optimization of the resin and sample size for ²³¹Pa recovery, ²³¹Pa/²³⁵U ratio have been studied in detail and are discussed. (author)