Low-loss liquid-core fibre-optical waveguides having a transmission loss of 10 dB/km has been made using commercially available glass tubing. The loss is less than 20 dB/km over a wavelength range of greater than 0.8–1.1 μm, and, at the semiconductor laser wavelength of 0.9 μm, has a value of 14 dB/km. This is the first low-loss fibre to be made using glass.