The localization of the epileptogenic zone (EZ) is crucial for the successful surgical treatment of epileptic patients who suffer from drug-resistant epilepsy. In this paper, we propose a new approach for EZ localization. The partial directed coherence approach and the outstrength parameter derived from graph theory are used to characterize the synchronization and desynchronization properties of brain structures and to categorize the corresponding channels into three groups referred to as the onset group, early propagation group and late propagation group according to their involvement in the seizure progress. Our results prove the effectiveness of the proposed approach, which corroborates the clinician's visual inspection and makes it possible to identify a set of channels that delimit the epileptogenic zone. The proposed approach for EZ localization can be considered a valuable tool for the successful surgical treatment of epileptic patients that suffer from the type of epilepsy considered.