The Huallaga–Marañon retroforeland basin system of northern Peru is deformed by both thick- and thin-skinned tectonics. The thrust system is complex and resulted from the reactivation of a west-verging Permian fold and thrust belt capped by an important salt detachment. This chapter presents 2-D petroleum modeling from an updated balanced cross section and sequential restoration through the Huallaga–Marañon wedge-top basin. The sequential restoration has been calibrated by thermochronological dating and thickness variations in Cenozoic synorogenic sediments. It shows two important stages of the deformation (Middle Eocene and Late Early Miocene). Late Triassic/Early Jurassic Pucara Group and Late Cretaceous (Raya and Chonta formations) classic source rocks are present in the Huallaga–Marañon foreland basin, but the revision of the stratigraphy replaced in its updated structural context allowed us to highlight a new Late Permian source rock (Shinai Formation). 2-D modeling of kerogens maturity evolution and hydrocarbon (HC) accumulations in the sequential restoration shows that first Andean structures (Middle Eocene and Late Early Miocene) could preserve HC accumulations in the Chazuta thrust sheet footwall. In the eastern Marañon basin, more recent structures (Late Miocene–Pliocene) such as Santa Lucia could also have been charged. Deep subthrust structures stay unexplored in the Peruvian fold and thrust belts. The Huallaga–Marañon foreland system is probably the best example of subtrap attractiveness in Peru.