In this Letter, we report for the first time the observation of CdS nanobelts. Using a simple thermal evaporation method. CdS nanobelts and nanowires with controllable growth positions were synthesized on tungsten substrates. To explore growth mechanisms of these nanostructures, we have examined the influence of temperature, substrate, and catalyst on their growth properties including morphology, composition, and internal structure. Compared with CdS nanowires. CdS nanobelts were formed in a higher temperature region. However, both growths were initiated by An catalysts. When silicon or porous silicon was used as substrates, SiO2 and SiO2/CdS composite nanobelts and nanowires were synthesized. The growth mechanisms of these nanostructures are discussed. (C) 2003 Elsevier B.V. All rights reserved.