Technical Abstract: Dutch elm disease (DED) has devastated native North American elm species for more than 75 years. The impact of DED on the genetic diversity of one native elm species, U. rubra or slippery elm, is summarized and its potential impact on the genetic diversity of the other four North American native elm species, U. americana, U. thomasii, U. alata and U. serotina is discussed. The potential for hybridization between the introduced U. pumila and the native North American elm species is considered in light of previous findings on hybridization between U. rubra and U. pumila. Given their wind-pollination system that can create strong gene flow and significant outcrossing, we do not expect DED to have reduced the genetic diversity of these native elm species. The only exception may be U. serotina if its more restricted range leads to genetic discontinuities among its populations. Moreover, while extensive hybridization has been detected between U. rubra and U. pumila, we do not expect much hybridization between U. americana and U. pumila because incompatibility barriers are present, in addition to differences in ploidy levels. Hybridization between U. pumila and the other three native elm species is more likely because no incompatibility barriers are known between these species. Hybridization with Siberian elm could have negative effects on the long-term conservation of four of the five North American native elm species but would spare the iconic American elm. This information is timely given the current efforts to restore American elm across the US landscape.