The rifting of Africa from North and South America has affected the structural framework off Liberia in two episodes. As shown by bathymetry, seismic-reflection profiles, magnetic data, and stratigraphy, the southeastern third of the margin is cut by west-southwest-trending fracture zones which we interpret as the extension of the St. Paul's fracture zone. These fracture zones intersect the continental margin off Cape Palmas to give rise to a blockfaulted and slump topography, similar to that in the area where the Romanche fracture zone intersects the African continent off Cape Three Points, Ghana. The fracture zones are covered by a prograded wedge of presumed Tertiary and Cretaceous sedimentary rock off central Liberia. Adjacent to the northwestern third of the Liberian margin, northwest-trending basins filled mainly with Lower Cretaceous paralic sediments are under the continental shelf; they extend to the upper slope, where they are downdropped along a northwest-striking fault zone that separates the shelf deposits from a thick prism of sediment beneath the continental rise. The southeastern third of the margin appears to have formed during the separation of Africa and South America in the Late Jurassic-Early Cretaceous. The rest of the margin seems, more strongly influenced by the tensional forces created during the rifting of Africa and North America; volcanic rocks are Late Triassic to Early Jurassic in age, and shelf sedimentation occurred mainly after the continents broke apart.