Ranaviruses are known to produce iseases in fish, amphibians and reptiles, being involved in high mortality episodes in aquaculture farms and in the decline of amphibian populations worldwide. Mass mortality episodes were previously detected in Triturus marmoratus from two lagoons of the Peneda-Gerês National Park (PGNP) (NW Portugal). Ranavirus-like particles were identified in tissues of diseased newts T. marmoratus and T. boscai. Here we report on the molecular and ultrastructural characterization of these viruses.