The article analyzes the changes that have characterized Spain’s approach to NATO in the post-Cold War era, and more specifically, the approach of different political parties to security and defense issues. If the People's Party is more Atlantic ideologically and traditionally, and therefore, is more in favor of strengthening cooperation with NATO, the socialists are increasingly pro-European and, therefore, advocate the strengthening of the European Security and Defense Policy (ESDP). Spain doesn’t question the necessity of NATO, the presence of American military forces in Europe in general and in Spain in particular as a method of security enhancing. Fears of marginalization caused the accession of Spain to this military organization after its eastward extension. In recent years, Spain’s influence and authority in NATO declined amid the economic crisis. This loss of authority will be overcome as soon as the economic growth is resumed. Notwithstanding that its ambitions in NATO and EU do not meet its possibilities, Spain is participating in different missions and naval exercises of the Alliance, and is constantly modernizing its military forces. Spain has always been indifferent to the hypothetical threat from the East, but is more than apprehensive to the threat coming from the situation in Libya, instability in Tunisia and especially an eventual destabilization in Morocco where Spanish cities Ceuta and Melilla are situated. Under the pretext of struggle against international terrorism, Madrid is trying to reestablish its influence in North Africa. Spain favors the transformation of NATO into an effective tool to prevent regional conflicts. The country's national interests will continue to determine its attention to problems of the Mediterranean and North Africa. The economic crisis has contributed to a drop in the objective value of bilateral relations with the United States and of Trans-Atlantic relations as a whole.