From an aqueous solution of uranyl nitrate hexahydrate and tetra-n-butylammonium nitrate, single crystals of the title compound, (C16H36N)(2)[U-2(NO3)(4)(OH)(2)O-4], were obtained. The structure features a dimeric hydroxo-bridged tetranitratodihydroxobis[ dioxouranate(VI)] dianion.