The Ultraviolet Coronagraph Spectrometer (UVCS) is an instrument onboard the Solar and Heliospheric (SOHO) spacecraft, a joint ESA/NASA mission to be launched in 1995. The purpose of the UVCS is to contribute a body of data that can be used to address a broad range of scientific questions regarding the nature of the solar corona and the generation of the solar wind. The primary scientific goals are the following: to locate and characterize the coronal source regions of the solar wind, to identify and understand the dominant physical processes that accelerate the solar wind, to understand how the coronal plasma is heated in solar wind acceleration regions, and to increase our knowledge of the coronal phenomena that control the physical properties of the solar wind as determined by in situ measurements. To progress toward these goals, the UVCS will provide ultraviolet spectroscopic measurements to be combined with plasma diagnostic analysis techniques that are expected to lead to a far more detailed description of the coronal plasma than presently exists. The UVCS is intended to determine the primary plasma parameters of the solar corona from its base to as high as 12 . It is expected to measure signatures of both thermal and nonthermal processes: electron temperatures, effective temperatures of protons and several minor ions (, , and ); electron and ion densities (, , and ); and flow velocities of the electron/proton plasma and of the minor ions , and . These measurements together with those obtained by the other coronal and in situ experiments on SOHO should address a wide variety of problems of solar wind physics.