We propose in this paper to study the economic and social thought of Friedrich Hayek, a leading figure of contemporary liberalism. More precisely, our goal is to present the broad lines of hayekian liberalism to describe its position on a specific question: that of the role of democracy in the determination of what constitutes a good society. By society, we mean, according to Hayek, the institutions – rules of conduct/constitution – which men, as social beings, can consider in their reciprocal relationships. The goal of our paper is thus one of knowing the place Hayek grants to democracy in the definition of good social rules: Is Hayek in favor of constitutional democracy? Our answer is negative: in contrast to economists such as James Buchanan and Viktor Vanberg, Hayek challenges citizen sovereignty on constitutional matters. And this, because he considers that this field concerns scientific analysis rather than democratic choice.