Nanocrystalline tin oxide particles were synthesized by injecting tetramethyl tin (Sn(CH3)(4)) into the center of a multi-element diffusion burner. The particle size, size distribution and composition were characterized using transmission electron microscopy and x-ray diffraction analyses. High purity SnO2 nanoparticles were formed with no trace of Sn or SnO impurities. The experimental approach was demonstrated as a valuable means to study SnOx particle nucleation and growth phenomena under controlled synthesis conditions.