This chapter begins by discussing factors affecting electoral participation and reviews turnout differences during the postwar period in our eighteen OECD countries. It focuses on changes in participation in Swedish elections since the introduction of universal suffrage and variations in turnout among different groups. The chapter examines some additional aspects of political involvement. Electoral participation is therefore a traditional area of interest in the social sciences. The United States and Switzerland stand out, however, as having the lowest electoral participation. Electoral participation is affected by various administrative and practical circumstances. With some significant exceptions, electoral participation in the Western countries has tended to increase since the breakthrough of political democracy, which occurred around World War I for many of these countries. The stable increase in electoral participation in Sweden indicates that the citizens view elections as meaningful acts significantly affecting their living conditions.