Multicomponent metal oxide (MMO) crystallites are prepared by spraying a reactant solution into a receiving solution or into air under microwave radiation at atmospheric pressure. The injection of a nitric acid solution through an ultrasonic nozzle into a receiving solution of metal precursor and the use of microwave radiation are combined to form a novel preparation technique called the nozzle-spray/microwave (NMW) method. The inclusion of an additional step, the in situ mixing of precursor solutions prior to their injection through the ultrasonic nozzle spray, leads to another procedure called the in situ/nozzle-spray/microwave (INM) method. For comparison, MMO materials with the same metal constituents as those prepared by our novel techniques are prepared by conventional hydrothermal (CH) methods. Fresh materials prepared by NMW, INM, and CH methods were heat treated to study the effect of calcination. All materials were characterized before and after calcination using X-ray diffraction, scanning electron microscopy, Brunauer-Emmett-Teller surface area, and inductively coupled plasma elemental analysis. The NMW method produces particles with rodlike morphologies different from those obtained using CH methods. The INM method produces an amorphous material that crystallizes after calcination into small (ca. 200 nm) particles with interesting morphologies. Notably, calcination of materials prepared by both NMW and INM reduces the particle size and increases the surface area. The work presented in this paper paves the way to use NMW and INM to prepare MMOs with unique morphologies.