In this study, the Plio-Quaternary to present-day stress regimes, acting in the Hatay region, which is located at the northeastern corner of East Mediterranean region, were determined. The modern stress state is obtained from inversion of focal mechanism solutions of shallow earthquakes. The inversion provides that the present-day stress field is dominantly extensional stress regime with NE-trending ?3 axis. The stress regime determined by inversion of slip-vectors measured on active fault planes confirms that the present-day stress regime is extensional in the study area. Both the fault kinematic analysis and the chronology between slip-vectors show that the stress state changed from old strike-slip to younger extensional stress regime consistent with NE-trending ?3 axis. The change between strike-slip and extensional stress regime probably occured during Quaternary time. The both stress regimes, consistent with NE-trending extensional axis (?3), induce left lateral displacement on East Anatolian Fault and Dead Sea Fault directions. The stress regimes prevailing in the Hatay region, result probably from the coeval influence of the boundary forces due to subduction i.e., Cyprus arc, in the southwest and to the thrust zone (Bitlis suture zone) in the northeast. However, we assume that subduction prosess played a dominant role to occurrence of NE-SW extensional stress regime in the Hatay region
