[en] The determination of uranium in concentrates and uranium-rich materials often requires a greater accuracy than fluorimetry, spectrophotometry or polarography offer. An accuracy of +-0.2 to 0.3% is achieved here (optimum uranium quantity 150 to 200 mg) by using the proposed simple titration method. It is based on the reduction of U VI to U IV by means of an iron-II-sulphate in concentrated phosphoric acid. Following selective oxidation of the excess iron, the U IV is titrated against potassium dichromate solution. If a few interfering factors are accounted for, the method may be applied to a larger range of uranium-containing solutions, e.g. also to TBP-containing extraction solutions of uranium. (RB)