The aim of this study was the synthesis of mixed or coated multicomponent alumina-silica particles by chemical vapour deposition method in a tube flow reactor. The particles were produced by simultaneous thermal decomposition of aluminum tri-sec-butoxide and tetraethylorthosilicate in one reactor. The particle production was monitored by Differential Mobility Particle Sizer, composition of particles was analysed by energy dispersive X-ray analysis, morphology by scanning/transmission electron microscopy and crystallinity by selected area electron diffraction. In dependence on experimental conditions, the particles produced were either alumina particles with intermixture of silica, or they were coated by silica, or it was a mixture of particles of various compositions. The particles were often agglomerates of the primary nanoparticles and were partially crystalline. (c) 2005 Elsevier B.V. All rights reserved.