Barley seeds (Hordeum vulgare L.), introduced from Argentina, were sown in Southern Chile giving rise to plants with black or yellow stripes on the leaves. The symptoms suggested the presence of barley stripe mosaic virus (BSMV). The plants were tested using mechanical transmission, electron microscopy, ELISA and PCR (Polymerase Chain Reaction). The results allowed the identification of BSMV as the causal agent of these symptoms in the infected barley plants. This is the first identification of the virus in Chile, and because the infected plants were localized in a specific place, all the material was eliminated by burning.