Uniform MoO3 single-walled nanotubes (SWNTs) have been successfully synthesized for the first time through a simple thiol-assisted hydrothermal method. TEM, HRTEM, EELS and XPS characterization showed that the as-obtained sample was composed of high purity SWNTs. We hope our endeavour could blaze a new path in the field of NT research, especially in the barely explored noncarbon SWNT areas.