This catalog contains data for a large number of objects that have been classified as cataclysmic variables (CVs) as well as a smaller number of objects that are now not considered to be cataclysmic variables, but were originally classified erroneously as such. As of 2000 December, 40% of the objects in this catalog were dwarf novae, with another 30% being novae, and the rest being mostly nova-like variables; also as of this date, a large fraction (90%) of the CVs had references to published finding charts, while 64% of the objects had published spectra. The catalog includes coordinates measured in the reference frame of the Hubble Space Telescope Guide Star Survey for non-novae and from the literature for novae. Also given are the variability type, the magnitude range, orbital periods, flags indicating the existence of relevant space-based observational datsets, references to finding charts and spectroscopy, the galactic latitude and longitude, and the year of outburst (for novae). This edition also includes plate identification information for the coordinate measurements, and a reference to the classification. The Catalog and Atlas of Cataclysmic Variables (Downes et al. in 2001, PASP, 113, 764 and <a href="http://archive.stsci.edu/prepds/cvcat/">http://archive.stsci.edu/prepds/cvcat/</a>;) presented here is the ASCII Report mentioned in Section 2.1 of the PASP paper, and is similar to the previously published versions of the CV Catalog (e.g., Downes, Webbink and Shara 1997, PASP, 109, 345, Table 1). The online version of the CV Catalog at <a href="http://archive.stsci.edu/prepds/cvcat/">http://archive.stsci.edu/prepds/cvcat/</a>; contains additional data on these systems not included in this database, including finding charts. For a complete authoritative and up-to-date description of the CV Catalog, refer to <a href="http://archive.stsci.edu/prepds/cvcat/description.html">http://archive.stsci.edu/prepds/cvcat/description.html</a>;, from which the HEASARC has constructed this help file. This HEASARC version of the CV Catalog was last updated in February 2006. This is a service provided by NASA HEASARC .