The catalog is a compilation of 518 extragalactic radio sources with flux densities greater than 1 Jy at 5 GHz. It contains sources from the NRAO-MPI 5-GHz Strong Source Surveys and from re-observation at 5 GHz of sources found in the Parkes 2.7-GHz surveys. All sources were found in 9.811 sr covered by the two surveys. This is essentially the whole sky, excluding the galactic plane (latitudes less than 10 degrees) and the Magellanic Clouds. The catalog includes radio flux densities, radio positions, object classes, visual magnitudes, redshifts, and spectral indices. Introduction: Codes for the position references are listed in this document in the appendix. In the main file, errors are given for all radio positions, flux densities, spectral indices, and function coefficients. See the original paper for discussions of the completeness of the catalog, of the compilation of the flux density data, and of the fitting of simple analytic functions to the spectra. The 1Jy catalog lists information on 518 objects with one to sixteen flux density values for each source. The file sources.dat lists the complete header information for each object. This line has been removed from catalog.dat. There are at most four density values in each record. Records containing fewer than four measurements are filled with blanks on the right. The first word of the file catalog.dat contains the id for the object. refs.dat contains a numerically sorted list of the radio source catalogs cited in the flux density measurement records. For each source catalog the original reference or references (usually one, but in one case as many as three) are listed, as well as the pertinent characteristics of the catalog. When more than one line was needed for a reference up to four continuation lines were used.