The catalog contains machine-readable versions of the "Catalog of CO Radial Velocities Toward Galactic HII Regions" (Blitz et al. 1982) and the "Catalog of Carbon Monoxide Observations of Southern Hemisphere HII Regions" (Gillespie et al. 1977) in two separate files. The former is a catalog of 242 molecular cloud complexes that are associated with optical HII regions and includes source names, coordinates, CO radial velocities, antenna temperatures and full width at half-maximum at the position of the strongest CO emission, references for the observations, distances to the stars exciting the HII regions, and optical diameters of the HII regions. The latter is the first CO survey of the southern sky; it was made using the Anglo-Australian 3.9-m optical telescope at 115GHz (2.6-mm wavelength) with a hot-electron bolometer receiver located at the Coude focus. The data were collected during two observing periods (September 1975, April 1976) and include designations, coordinates, median values for the velocities, and distances to the stars exciting the HII regions.