The regional tectonics and the mid to late Quaternary seismic stratigraphy of the Strait of Canakkale (Dardanelles) and its opening towards the Aegean Sea were interpreted by using shallow seismic profiles. This strait is a narrow valley that resulted from regional uplift of the Gelibolu and Biga Peninsulas in the Pliocene as a consequence of compressional events generated by strike-slip faulting activity of the Ganos Fault, a northern strand of the North Anatolian Fault. A NNE-SSW trending fault system between Eceabat and Canakkale, believed to result from the left lateral displacement of the Ganos fault on the Gelibolu Peninsula, cut this valley into different segments. The connection between the Marmara Basin and the Aegean Sea has been achieved after flooding of the connected valleys during the mid to Late Pleistocene. Three major sea level lowstands (-130/ -150 m) during this period (similar to 600 kyear BP) interrupted the sea water connection at least twice. Three main seismic unconformities detected in the sediments of the Strait of Canakkale represent these lowstands. Minor sea level lowstands could have induced narrowing of the strait and erosion of depositional units. The recent geological history of the Strait of Canakkale appears, as deduced from the Gelibolu Peninsula and its western regions, strongly related to escape tectonics influenced by the compressional forcing of the Anatolian Block. In addition, it also shows a morphological evolution, which carries the effects of the global sea-level variations. (C) 2000 Elsevier Science B.V. All rights reserved.