A differential pulse polarographic method was developed for the determination of total uranium In 238Pu metal and oxides. A supporting electrolyte of 0.5 M ascorbic acid in 0.15 N H2S04 was found satisfactory for the determination of 500 ppm or more of uranium in 10 mg or less of plutonium. A relative standard deviation of 0.27 to 4.3% was obtained in the analysis of samples ranging in uranium content from 0.65 to 2.79%. The limit of detection was 0.18 /ug ml-1. Peak current was a linear function of uranium concentration up to at least 100 /ug ml-1. Amounts of neptunium equal to the uranium content were tolerated. The possible interference of a number of other cations and anions was investigated.