In Spain the evaluation of the education system is viewed as an essential element in order to improve the quality of education, since it constitutes a valuable instrument for the monitoring and assessment of both the functioning and the results of the education system, as well as for the improvement of the processes delivering these results. The Spanish education system was globally evaluated for the first time in 1976, when the Nation's Government commissioned the evaluation of the results obtained after the enactment of the 1970 General Act on Education and Financing of the Educational Reform (LGE). This paper discusses the objectives, organization, and use of results of the national testing of pupils in Spain. This paper contains the following parts: (1) General Overview of Pupil Assessment; (2) Historical Background to National Testing and its Political Framework; (3) Aims and Organizations of National Testing; and (4) Impact of National Testing.