A new combined single step gamma-spectrometric and passive X-ray fluorescent measurement method and a corresponding procedure have been developed. Only one gamma-X-ray spectrometric measurement is required in order to determine both235U enrichment and U-total concentration of the measured sample. In this way, if the sample is homogeneous and weighted, the total quantities of U-total and235U can be determined. The main advantages of this approach over the enrichment measurement method used are: (1) the U-concentration of the measured material is determined; (2) the235U enrichment is determined more reliably and accurately. The matrix of the material, which influences the enrichment measurement, is also determined and taken into account.