Nanoparticles of Ru-Ni-S were synthesized in a single-step spray-pyrolysis process as potential catalysts for fuel cells and other applications. The application of methanol as solvent had a strong effect on the particle morphology, size, and composition. The pyrolysis temperature strongly affected the particle morphology when methanol was used as solvent. High temperatures promoted dendrite formation. When a water/methanol mixture was used as solvent, crystalline ternary nanoparticles of Ru-Ni-S on a carbon layer were formed at lower temperatures. A very interesting and unique structure of spherical clusters of crystalline particles attached by a chain of crystalline nanoparticles was synthesized. This is an abstract of a paper presented at the 2007 AIChE Annual Meeting (Salt Lake City, UT 11/4-9/2007).