<p>Cholesterol plays an important role in cell membranes through its influence on the membrane structure, stability, dynamics and phase equilibria which ultimately impact many membrane functions. Of the experimental techniques used to study the role of cholesterol in membranes, nuclear magnetic resonance is uniquely capable of providing detailed information on the molecular level as well as describing macroscopic properties such as membrane phase equilibria. This article describes three different aspects of cholesterol in model membranes: the orientation, order and dynamics of cholesterol in the lipid bilayer; the fluid-fluid two-phase coexistence found in ternary mixtures of saturated and unsaturated phosphatidylcholines with cholesterol; and the critical behaviour of these same ternary mixtures.</p>