Submicron particles comprising nanocrystallites of Gd0.1Ce0.9O1.95 (GDC), NiO-Gd0.1Ce0.9O1.95 (NiO-GDC), and La0.8Sr0.2CoO3 (LSC) were synthesized using ultrasonic spray pyrolysis in a reactor at 1,273 K for 13 s. Nitrates of the component metals were used as precursors and dissolved in pure water in stoichiometric amounts of GDC, NiO-GDC, and LSC. GDC and NiO- GDC were spherical, whereas LSC were nonspherical. The crystalline nature of GDC improved on increasing the reactor temperature from 773 to 1,273 K during the reaction time of 13 s. The average sizes of NiO-GDC and LSC crystallites prepared using the solution concentration of 0.2 mol L-1 were bigger than those prepared using 0.02 mol L-1 solutions.