The ESCI-València Trough deep seismic reflection profile crosses the eastern margin of Iberia and can be divided into three regions according to crustal structure. From NW to SE they are: a) the Ebro Basin, whit a 33 km thick continental crust wich remained almost undeformed during the Cenozoic and is very reflective in its lower part; b) the Continental Margin, made up of the Catalan-Valencian Domain and the Balearic Promontory with a thin (12 to 30 km thick) continental crust wich was deformed during the Cenozoic, extensional structures predominating the first domain and contractional structures in the second; and c) the Algerian Basin, with a 9 km thick oceanic crust. The oldest Cenozoic structures registered in the profile are contractional. During the Palaeogene, these structures affected the NW part of the Catalan-Valencian Domain and enabled this domain to be thrust over the Ebro Basin. During the Early and Middle Miocene, The extensional structures of the Catalan-Valencian Domain were formed in association with crustal thinning. At the same time, the contractensional structures were produced in the southern part of the Balearic Promontory in association with the formation of the oceanic crust. The displacement of the observed extensional faults is not sufficient to explain the crustal thinning. This implies that, during the Cenozoic, either crustal volume decreased or there were important faults that cannot be observed. It is suggested that a low angle fault of great displacement, that crosses the whole upper crust, may have existed prior to the Middle and Upper Miocene sediments. The thinning of the lower crust would have been schieved by an array of shear zones.