The Geosynchronous Imaging Fourier Transform Spectrometer (GIFTS) instrument, under development for the NASA New Millennium Program, will serve as a valuable test bed for the evaluation of new hardware and software approaches in the years leading up to NOAA's operational Hyperspectral Environmental Suite (HES). The GIFTS sensor makes use of a 2-D array of detectors to increase area coverage rates while providing dramatically higher vertical resolution by measuring the thermal infrared upwelling emission spectrum at high spectral resolution. The sensor calibration makes use of two internal high precision blackbody references in addition to an external view to space. The GIFTS ground data processing algorithms used to convert from instrument values (Level 0 data) to geo-located, calibrated radiances (Level 1 data) are under development at the University of Wisconsin Cooperative Institute for Meteorological Satellite Studies (UW-CIMSS). These algorithms include geo-location, non-linearity correction, calibration, and correction for off-axis effects. This paper provides a description of the Level 0-1 GIFTS algorithms and their performance characteristics.