Significant levels of 14C have been detected in uranium-bearing minerals using the tandem accelerator mass spectrometer at the University of Arizona. The amount of 14C detected in a given mineral is proportional to the concentation of uranium in that mineral. The average value of 14C atoms/uranium atom is (2.2¿0.5)¿10-15 (2&sgr;). These data are consistent with the assumption of direct 14C emission from one or more nuclei in the 238U decay chain with a branching ratio of 1.0 to 2.0¿10-9, relative to alpha decay. The uncertainty results from the possible production of 14C from 11B(&agr;,p)14C.