This report by the European Commission presents the findings of the fourth post-programme surveillance mission to Spain and identifies remaining challenges for the Spanish economy. This fourth surveillance report provides an assessment of Spain's economic, fiscal and financial situation following its exit from the financial assistance programme in January 2014. A team from the European Commission, together with staff from the European Central Bank (ECB), carried out a fourth post-programme surveillance visit to Spain on 5-8 October 2015. The European Stability Mechanism (ESM) participated in the meetings on aspects relating to its early warning system. The report also covers the Commission's specific monitoring of policy progress in the context of the macroeconomic imbalances procedure (MIP).