A new saxicolous species of semifruticose lichens, Roccellina olivacea FOLLM. (Roccellaceae, Arthoniales), affined to Roccellina condensata DARB., is described from the coastal belt of Centrai and North Chile, South America. Its morphological, chemical, chorological, ecological, and sociological characteristics are briefly discussed. A key to the species of the East Pacific genus hitherto known is also provided.