This is a catalog of 242 molecular cloud complexes which are associated with optical H II regions. CO observations were made toward all but five of the H II regions in the Sharpless catalog and toward 62 additional suspected H II regions, 33 of which are previously uncataloged. Radial velocities are tabulated for each molecular cloud complex found to be associated with an H II region. The CO antenna temperature and line width are given for the most intense CO line seen toward each source. The catalog also summarizes previous CO observations as well as the optical distances to the stars exciting the H II regions. Radio-quiet H II regions (those with 1.4 GHz flux densities less than 100 mJy) are found to be well correlated with objects having no associated CO. A list of kinematically distinct complexes is tabulated to facilitate investigations of the motions of the complexes.