This article describes the development, construction, and performance characteristics of a small, low-mass, low-power-consumption vacuum pump for use at pressures down to 5 x 10(-2) Ton The pump is based on a peristaltic tubing pump modified to overcome rapid tubing deterioration problems normally encountered when peristaltic pumps are used for vacuum pumping. Typical uses of the pump are for portable scientific and engineering instruments requiring pressure and flow characteristics compatible with the pump. These include the backing of high-vacuum pumps, rough-pumping vacuum systems used with certain ion and cryosorption vacuum pumps, and interstage pumping of membrane separators.