The Antarctic Fiber Optic Spectrometer (AFOS) is one of a suite of instruments of the Automated Astrophysical Site Testing Observatory (AASTO) installed at the South Pole in 1996 December. In 1998, the AFOS will be attached to an altitude-azimuth mount and commence regular astronomical observations. In the years 1998-2000, the AASTO will be moved to other remote locations, high on the Antarctic plateau, in order to complete the site testing campaign. The AFOS experiment consists of a 30 cm Newtonian telescope injecting light into a 45 m length of optical fibers that feed a UV-visible (200-840 nm) grating spectrograph inside the warm shelter. In this paper we describe the instrument and the first results. The main requirement of the design was reliable operation in an extremely cold environment, without maintenance, for 12 months. This has been achieved despite the very low power (approximately 7 W) available to run the instrument.