Abstract: Although uraninite is recorded in the granite pegmatite of south Sinai, this study represents the first record of uraninite in fluorite –bearing quartz veins in south Wadi El -Barrah area, south Sinai. Wadi El- Barrah is a tributary of the famous Wadi Akhdar which can be accessed through the asphaltic road reached to Saint Katherine city. The area is covered with older granites, monzogranite, quartz syenite, pre-syenogranite dykes, syenogranite and post syenogranite dykes. The area is affected by numerous strike-slip faults and related fractures with NNE-SSW, NW-SE and NE-SW directions. The NNE-SSW and NE-SW fractures are filled with fluorite-bearing quartz veins where some of them show high radioactive intensities. The radiometric study that carried out on these fractures and the associated fluorite –bearing quartz veins indicates that eU ranges from 370 to780 ppm while eTh ranges from340 to 810 ppm. This abnormal radioactivity is attributed to the presence of uraninite, uranosphaerite and thorutite minerals. Uraninite is of hydrothermal origin as indicated by the presence of galina and deep violet fluorite while uranosphaerite is an alteration product of the uraninite.