Abstract: A methods of spectrophotometric determination of small amounts of uranium with chromazurol S (CAS) in the presence of non-ionic surfactants Triton X-100 is investigated. The color of the complex formed is blue at a pH of 5.9. The complex has a composition of U: CAS :TX-100=5:5:1 and the molar extinction coefficient at 640 nmmn is 6.0×104.A number of ions which interfere with the determination can be masked by the addition of various masking agents.