Rotaviruses (RVs) are a major cause of neonatal diarrhoea in humans and numerous animal species. We report G-type, P-type and phylogenetic analysis of two RV strains isolated from newborn guanacos (Lama guanicoe) with acute diarrhoea in Argentina. Isolates were group A G8 RV. Phylogenetic analysis showed a close relationship to other G8 bovine RV from Japan, U.S.A. and Switzerland. P-types were P[1] and an unusual P[14], related to human and goat P[14] strains. This is the first report of a P[14]G8 strain in our country and the first study on molecular epidemiology of rotavirus found in a new species.