Abstract: This paper describes the synthetic methods of four new complexes of dioxouranium (VI) with hydroxamic, acid. The structures and characterization of some of them have been elucidated on the basis of infrared spectra, ultraviolet spectra, fluorescence spectra, NMR spectra, thermogravimetric analysis, X-ray diffraction and chemical analysis. The stability constants and molecular conductance of complexes have also been studied.