The use of salicylamidoxime as a reagent for the spectrophotometric determination of uranium, by making use of the orange-yellow colour formed by uraniumvi with the reagent in alkaline solution, is described. The optimum wave-length fur measurement of the colour intensity is 400 m\(\mu\) ; the pH of the solution should be within the limit of 7.9-9.2, and an excess of the amidoxime, at least seven times the molar proportion of uranium, is essential, The colons is stable at room temperature and its intensity is independent of temperature within the range of 20o-25o, but measurements can safely be carried out at temperatures up to 30°. Beer's law holds good within the range of 7-145 p. p. m. uraninm, and sensitivity is 0.12 \(\gamma\) cm-2. The composition (1 : 1) of the coloured species has been evaluated by job's method and the probable constitution has been assigned. Most cations and anions interfere with the determination of uranium. Hence, a preliminary separation of uranium from the interfering ions is essential as in most other cases