We have constructed a spray dryer to synthesize doped ceria nanoparticles. The system was employed to synthesize mixed oxide nanoparticles of praseodymium doped CeO2 (Ce0.97Pr0.03O2, Ce0.90Pr0.10O2, and Ce0.80Pr0.20O2). X-ray diffraction confirmed the fluorite-like cubic crystal structure of the synthesized materials after heat treatment at 700 degrees C for 2 h. As-dried CeO2 samples were found to have an average particle size of (6.0 +/- 0.2) nm which increased to (17.0 +/- 0.4) nm after heat treatment with an improvement in crystallinity. The particle size increased steadily with Pr content. The lattice parameter of Pr-doped CeO2 was found to increase or decrease with Pr content depending on the heat treatment process. (C) 2010 Elsevier B.V. All rights reserved.