Praseodymium-doped ceria (CeO2) nanopowders have been synthesized via a simple but effective carbonate-coprecipitation method, using nitrates as the starting salts and ammonium carbonate as the precipitant. The precursors produced in this work are ammonium rare-earth double carbonates, with a general formula of (NH4)(0.16)Ce1-xPrx(CO3)(1.58).H2O (0 < x less than or equal to 0.20), which directly yield oxide solid solutions on thermal decomposition at a very low temperature of similar to400degreesC. Praseodymiurn doping causes a gradual contraction of the CeO2 lattice, because of the oxidation of Pr3+ to smaller Pr4+, and suppresses crystallite coarsening of the oxides during calcination. Dense ceramics have been fabricated from the thus-prepared nanopowders via pressureless sintering for 4 h at a low temperature of 1200degreesC.