Ultraviolet spectroscopy with the IUE satellite has been used to survey all Cepheids brighter than 8th magnitude to identify blue companions. The derived binary frequency is 21% with blue companions which implies that 34% would have been found from a large radial velocity survey. A second study has used deep IUE exposures of Cepheids showing orbital motion to determine the distribution of mass ratios in Cepheid binaries. Low mass companions are strongly preferred, especially when corrections for incompleteness are included.