According to the author of the paper, elections perform many functions. The paper focuses on the legitimacy function. In the first part of the paper the concept of legitimacy is briefly characterized, with reference to the classic concept of Max Weber and the distinctions developed by David Easton and David Beethem. The second part focuses on the problem of democratic legitimacy for which electoral legitimacy is essential.In the last part of the paper, is also pointed out that no matter what the political system is - democratic or undemocratic - voting turnout is one of the most important legitimizing factors.