Spain has one of the highest rates of imprisonment in the European Union. The reason for the high rate of imprisonment is thought to be due to the severity of the prescribed penalties which became harsher after the enactment of the 1995 Penal Code. This article describes the Spanish penitentiary system and points to how close the Spanish penitentiary system comes to fulfilling the ideal role for the prison in the system of punishment based on the significant prison renovation program in the 1990s and based on three propositions: limitation of the use of imprisonment, normalization of prison life, and early reintegration into society of prisoners in the process of rehabilitation. These propositions are reflected in legislation, the Penitentiary Law of 1979, and the Penitentiary Rules of 1996. The article reviews the various aspects of these three propositions. Tables and references