The topicality of the addressed subject resides in the interest shown in knowing extradition as a form of international legal assistance in criminal matters. In achieving the collaboration of the states in the fight against the criminal phenomenon, extradition has a special role, being the form of legal assistance that the states resort to most often in the activity of crime prevention and repression. For the Republic of Moldova, as a unitary and independent state, extradition is a relatively new institution, which appeared as an inevitable consequence of the state's fight against crime. The premise of its appearance was the fact that the Republic of Moldova declared itself an independent and sovereign state. The main role of extradition is to provide each state with the best conditions for the realization of justice in the repression activity. This requirement is fulfilled whenever the criminal is tried and punished by the state whose law he violated, or, the execution offers the states the opportunity to fulfill this requirement, obviously constituting a proof of solidarity embodied in the acceptance by each state of the obligation to to deliver the criminals to the justice of the state whose public order was disturbed. In this way, the legislations that provide for the unlimited criterion, for crimes committed outside the territory, thus enshrining the principle of universality, subordinate the application of their own rules, giving preference to extradition. Only when extradition for certain reasons would not work, the state in whose territory he took refuge will, with the subsidiary title, apply its criminal law. Through international or bilateral conventions, the signatory states have established three systems for granting extradition, according to the legal mechanism used and according to the system of which the state authority that receives the request, fulfills the formalities and decides on the extradition is a part. The Republic of Moldova adopted the mixed system of granting extradition.