Abstract: Uranium has been detected in fluid inclusion decrepitates from quartz of several granites of the British Isles and from vein quartz associated with the Hcrcynian granites of SW England using ICP. Material, ejected from the inclusions during decrepitation on heating the sample, is transferred into the plasma for qualitative analysis via a stream of argon. Several other elements have been detected in the decrepitate, of which carbon is of particular interest. It shows a strong positive correlation with U and indicates the importance of C (presumably as carbonate complexes) in the transport of U in hydrothermal systems. Approximate order of magnitude estimates of the average U contents of fluid inclusions from the SW England samples, based on the assumption that U in the decrepitates is principally derived from the fluid inclusions, range from less than one to over a thousand ppm. Fluid inclusions may therefore be important in contributing to the levels of U reported in quartz (0.1 to 10 ppm).