The article describes aspects of gamma-spectrometric method for monitoring the percentage of natural uranium in technological solutions. A method for determining the minimum detectable activity for radiometric and spectrometric applications is proposed. The measurements and calculations results of the natural uranium minimum detectable activity in technological solutions for various gamma-ray spectrometers are given. Gamma-ray spectrometers with HpGe detectors may be used for the continuous monitoring of uranium in solution at any ratio natural uranium and 234Th and a wide range of uranium concentrations from 1 mg/l to hundreds g/l. Gamma-ray spectrometers with scintillation detectors are suitable for solving this problem, if radioactive ratio between natural uranium and thorium is known and without other radionuclides. Multizone processing spectra algorithm and is considered and it is shown his preference for the processing of the spectra obtained for gamma spectrometers with scintillation detectors. As a comparison, the estimate of minimum detectable activity of uranium is given for gamma-ray spectrometer with LaBr 3(Ce) detector in conditions similar to those measured for other gamma-ray spectrometers. It is shown that the spectrometers with LaBr 3(Ce) crystals more relevant to the measurement of large activities such as technological solutions enriched uranium.