The Defense Meteorological Satellite Program (DMSP) Special Sensor Microwave Imager/Sounder (SSMIS) is a 24-channel passive microwave radiometric system that measures atmospheric, oceanic and terrestrial microwave brightness temperatures. The National Oceanic and Atmospheric Administration's (NOAA) National Climatic Data Center (NCDC) archives and distributes SSMIS data collected from October 2003 to present (including pre-operational data). Passive microwave satellite measurements from SSMIS have been sparingly used for climate and precipitation applications due to the lack of corrections for solar intrusion (F-16 SSMIS), reflector emissivity (F-16 and F-17 SSMIS), and antenna pattern correction (APC) coefficients (F-16, F-17 and F-18 SSMIS). In order to address these problems, existing Unified Pre-Processor (UPP) code for numerical weather prediction (averaged and re-mapped SSMIS temperature record) applications was modified for climate and precipitation (CP) applications at native resolution. Scan non-uniformity, spillover and cross-polarization coefficients (APC values) were also developed for all DMSP platforms currently flying the SSMIS. This effort to use UPP-CP techniques to correct SSMIS data represents a significant first step toward preserving and increasing the climate data quality of this key passive microwave dataset.