UV observations of cataclysmic and symbiotic variables with the lUE satellite have given and are giving a fundamental contribution to our knowledge of the nature of these objects. The study of the UV resonance and intercombination lines of the most abundant elements has been used as a diagnostic of the physical conditions
in the disk, circumstellar region, and ejecta. Most objects display a strong UV continuum which is usually attributed to emission from the hot component and/or from the accretion disk. The exceptionally long lifetime of lUE has allowed the study of these objects during different activity phases. In the recurrent nova T Cr B dramatic UV variations have been observed during phases of optical quiescence. Of particular interest has been the UV study of the recent outbursts of the symbiotic stars AG Dra, Z And, and PU Vul, as well.that of CH Cyg during the activity phases associated to the formation of a jet. The results of multi-frequency observations (from raďio to x-rays) of some symbiotic variables and their implications for the models are also discussed.