A method of energy dispersive X-ray fluofescence analysis of U, Np, Pu contents in solution has been developed for application in the field of VVER spent nuclear fuel reprocessing. Precision is 0.4% in the range of the U contents 0.2–2‰, and the detection limit is 0.15 ppm. Preliminary dilution is required for solutions with hihg U contents (>3‰). Spectra treatment program for a minicomputer has been developed and the method of corrections for non-linearity of concentration curves was checked.