The preparation of silicon nanotubes (SiNTs) using nanochannel Al2O3 as a template and a chemical vapor deposition process is reported. The outer diameters of the SiNTs are around 60 nm with walls approximately 10 nm thick consisting of crystalline and amorphous silicon. A conceptual model is presented (see Figure) to account for the formation of SiNTs (right) as opposed to nanowires (left).