Abstract: A method for the determination of small amount of uranium in technological solution containing plutonium by X-ray fluorescence analysis is presented featuring selective excitation, selective absorption and the use of scattered radiation as internal standard. An X-ray tube source with a. molybdenum anode and a Si (Li) detector are used. By measuring the ratio of ULa X-ray to the scattered MoKa X-ray in the sample, the concentration of uranium is obtained accurately. Variations of concentration of Pu, Fe, HNO3, F. P. and instability of X-ray source have only minor influence on the determination of uranium. The measuring time is 10 min and the method can be used for analysis of samples containing 0-200 mg/1 of uranium with a standard deviation of≤±3 mg with 8 mg/1 as the lowest limit of detection.