The project, funded by the German Marshall Fund of the United States, aimed to continue the in-depth analysis of the Transatlantic Trends dataset – Transatlantic Trends: Immigration (2008-2013). It focused on studying the opinions and attitudes towards immigration of citizens from five European countries (France, Germany, Italy, Spain, and the United Kingdom) concerning the integration of migrants. The analysis sought to identify the key determinants in shaping perceptions regarding the integration of immigrants. The study specifically examined various types of integration perceptions expressed by European citizens, including the perception of integration of immigrants in general, second-generation immigrants, and Muslim immigrants. The research results were presented at the REPS-Espanet Congress in Barcelona from February 4-6, 2015, and are documented in two working papers: one presenting the overall findings and another focusing on the Spanish case.