The Karacasu and Bozdogan basins, which trend obliquely to modern grabens in the Central Menderes Massif, are investigated in terms of morphology, basinfill architecture, and structure. Evaluation of the previous geophysical and new structural data indicates that the basins are symmetrical grabens mostly running in a N-S direction. Analysis of sedimentary facies of the basins' infill supports the simple graben model by revealing lateral alluvial/colluvial fans in basin margins and axial fluvial/lacustrine environments in a central trough. The long-term changes between fluvial and lacustrine conditions in the basins are attributed to paleoclimatic origin. Paleostress analysis of slickensides substantiates that the basins were deformed under E-W extension and related N-S compression in the Late Miocene times, and this stress field would have been started in early Miocene times parallel to the Buyuk Menderes Graben (BMG). Following a basin-wide unconformity related to a short-lived compression in mid-Pliocene times, the stress field changed to a N-S extension as a result of the onset of the Buyuk Menderes Detachment in the north in the Late Pliocene-Early Quaternary. Emergence of the modern BMG bounded by high-angle normal faults in the north caused a progressive drop of base level and resulted in southward-developing fluvial incision since the Late Quaternary in the studied basins.