We report the detection and characterization of a novel gammaherpesvirus in the critically endangered Darwin's fox (Lycalopex fulvipes; syn. Pseudalopex fulvipes) on Chiloé Island, Chile. Out of 28 analysed blood samples stored in alcohol, four were positive for this herpesvirus using a previously described pan-herpesvirus PCR assay targeting the herpesvirus DNA polymerase. Positive samples were subsequently characterized by means of a PCR targeting a 500 bp fragment of the glycoprotein B of the gammaherpesviruses. This novel herpesvirus was most closely related to other gammaherpesviruses from terrestrial carnivores, and is tentatively named Darwin's fox gammaherpesvirus. No apparent lesions were observed in the surveyed foxes. This is the first report of a gammaherpesvirus infecting a canid worldwide, and also of one infecting a carnivore from South America. © 2013 SGM.