The sodium present in triple sodium magnesium uranyl acetate may be determined indirectly by reduction and titration of the uranium. The method appears to offer advantages over other methods in respect accuracy when quantities of sodium below 10 mg. are to be determined. The volumetric method gives significant evidence of the constancy of composition of the precipitates obtained from amounts of sodium ranging from 0.01 to 0.02 g. Although the percentage of UO₂ is somewhat higher than the theoretical value in precipitates of small weight, the ratio of sodium to uranium in these precipitates appears to be constant in the range studied. At technique for the rapid indirect determination of uranium or of sodium has been developed.