The aim of this paper is to evaluate the impact of the Spanish pension reform enacted in 2011. We use an accounting model with heterogeneous agents and overlapping generations in order to project revenues and expenditures of the pension system for the next four decades. Specifically, we analyze the impact of changes in the replacement rate, in the period of calculation and the delay of the retirement age. We obtain results under two alternative migration scenarios: (i) a combination of the latest figures released by the INE, which forecast a reduced annual immigration net flow of some 70,000 persons; and (ii) a revised scenario featuring a more generous hypothesis concerning this net flow. We demonstrate that the results show that these three changes instigated by the reform could imply a savings of about 3 percentage points of GDP in 2051. However, we couldn’t include in the evaluation the sustainability factor (that transform the Spanish system in a defined contribution scheme) that will start in 2027 due to the lack of details in the text of the Reform. Finally, we analyze the changes in average pensions by gender, skill, and nationality