Abstract: Sub-Andean retro-arc foreland basins in the western margin of South America are important petroleum accumulation and production zones, and develop in three different tectonic settings: evolvement of Caribbean plate superimposed Andean-type foreland compressive deformation in the north; Sub-Andean foreland basins were in long-term the Gondwana continental marginal setting, subsequently subducted by oceanic plate and thrusted by Andean orogenesis in the middle; the shapes and evolvement of basins in Patagonia were more influenced by Gondwana breakup and opening of Atlantic in the south. Based on the evolvements and petroleum characteristics, the sub-Andean retro-arc foreland basins in the western margin of South America could be divided into 6 segments.

Key words: western South America, sub-Andean, retro-arc foreland basins, segment characteristics