We have relocated 364 earthquakes in western Turkey between 2002 and 2003 using more than 45,000 accurate P and S differential travel-times. We also have determined moment tensors for 71 of these earthquakes using their broadband regional waveforms. After relocation the events are highly concentrated in three clusters and delineate two nearly vertical faults. Their strikes agree with the strike of one of the fault planes of the averaged fault-plane solution of the cluster, which allowed us to pick the true fault plane and the slip direction. We identified a NNW-striking left-lateral strike-slip fault near Buldan that connects the Gediz graben in the north and the eastern end of the Buyuk Menderes graben in the south. The other right-lateral strike-slip fault near Izmir strikes ENE--WSW direction. Our results indicate that part of the N--S extension occurring in western Turkey is accommodated by strike-slip faults and is accompanied by E--W shortening.