What kind of institutions is most essential to be trustworthy in order for a society to function well? To the extent that previous research has addressed the problem, trust in electoral, judicial and economic institutions and in public administration have been most frequently mentioned as most important for the functioning of society. The problem, however, is worth a more thorough research approach, where trust in different kind of institutions is systematically compared across political systems. The study is based on five different data sources: three aggregated datasets (CSES, WVS and ESS), and two surveys of Swedish citizens (SOM and the Lore Citizen Panel). When it comes to regime support (and legitimacy) institutional trust matters; especially trust in electoral and judicial institutions. Quality of government matters also. Economic factors, however, matter less in this instance. Political factors rule, not economical. Nations succeed when there is trust in electoral and judicial institutions and when there is an impartial public administration.