Detailed subsurface studies of the northern part of the Suez Rift and adjacent areas indicate the superposition of two different episodes of deformation. During the earlier (Late Cretaceous) phase of deformation, folds with NE-SW oriented axes were formed in northern Egypt as a result of convergence between Africa and Eurasia and the closure of the Neotethys. During the later (early Miocene) deformation, NW-oriented normal faults were formed as a result of the opening of the Suez Rift. Borehole data have shown that a belt of NE en echelon folds with NE-SW axes exists in the subsurface in the northernmost part of the rift, between Ayun Musa and the Sukhna-1 well, south of Gebel Ataqa. This fold belt represents the SW continuation of the en echelon folds exposed in the Mitla Pass, to the NE of the rift. Another pre-rift structure is the offshore extension of the Wadi Araba structure as a SE-facing monocline. This offshore structure also represents the continuation of the Gebel Somar structure, on the eastern shoulder of the Suez Rift The Gebel Somar and Wadi Araba structures represent the southernmost pre-rift fold in northern Egypt. Pre-rift folds in the study area stood high above sea-level during the Palaeocene and early Eocene. Upper Cretaceous and/or older rocks in the cores of these folds were later unconformably covered by middle Eocene rocks. The presence of Late Cretaceous folds should be taken into consideration when exploring for hydrocarbons in this part of the Suez Rift. Borehole data in NE Egypt also indicate the presence of Late Cretaceous folds underneath the almost flat-lying Tertiary rocks in the northern part of the Eastern Desert. These folds are considered to be potential hydrocarbon traps in this relatively poorly-explored area.