A Bi2V1-x-yUxBiyO5.5+0.5x-y solid solution derived from Bi4V2O11 has been prepared and characterized with x up to 0.125 for y = 0. Partial substitution of U6+ for V5+ in Bi4V2O11 leads to the stabilization at room temperature of the high-oxide ion conducting gamma-phase, in contrast with other M(6+) dopants which stabilize the beta-phase. The lower conductivity in U substituted system compared with BICUVOX.10 is attributed to its higher activation energy. Conductivity values and activation energies of the U substituted phases compare well with Bi2UO6.