A paleoseismology study has been conducted on the faults of the SW margin of Denizli graben (Southwestern Anatolia) for the purpose of understanding its seismic behavior in historical periods. Samples have been taken from Holocene aged sediments coming onto the young faults of the graben especially in Duacili quarry and Almadan trench taking place in Saraykoy zone and radiocarbon analysis has been conducted. In this respect, the first seismic event occurred in Almadan trench between 4170-3960 B.C. The third seismic event occurred between the years 360-90 B.C. again in the same location and on the same rupture. This earthquake probably has a magnitude of approximately 6.5 and it has formed a 40 cm dip slip. About 11-14 km surface rupture has occurred in this earthquake. The second seismic event between these two earthquakes occurred on Duacili segment taking place in southern zone between 1920-1730 B.C. It is understood from the obtained data that a bigger earthquake has occurred when compared to the third tectonic event. Upon these data, it could be said that the earthquakes in SW margin of the graben have a recurrence interval changing between 1600-2300 years.