This paper focuses on the four large intracratonic (or interior) sag basins of Brazil: the Solimoes, Amazonas, Parnaiba, and Parana. The smaller Chaco basin also is discussed, although in less detail. The Dolimoes basin has the greatest initial estimated undiscovered reserves of oil (0.04 BBO), and the Parana basin has the greatest initial estimated undiscovered reserves of gas (5.08 TCFG). The most important plays in the Solimoes and structurally similar Amazonas basins are the fold and fault closures associated with the wrench systems found in the basins. The plays in the Parana basin are limited to possible structural traps linked to fault-associated closures, and possibly to some wrench-related features.