Sets out a spectrophotometric method for the determination of uranium (VI) in both fresh waters, in the concentration range 0.12 mg/L to 16 mg/L and saline waters in the range 0.3 mg/L to 40 mg/L. A preliminary chelating resin separation extends the application of the method of polluted and waste waters for the uranium (VI) concentration range 0.12 mg/L to 16 mg/L.