Abstract A 15-ns molecular dynamics simulation of the fully hydrated liquid–crystalline dimyristoylphosphatidylcholine–cholesterol (DMPC–Chol) bilayer containing ∼22 mol% Chol was carried out. The generated trajectory was analysed to investigate the mechanism of the Chol condensing effect on DMPC hydrocarbon chains and the influence of Chol on the chain packing in the membrane. Chol was found to induce stronger van der Waals interactions among the chains, whereas its interactions with the chains were weak. In the DMPC–Chol bilayer, as in the DMPC bilayer, DMPC chains were regularly packed around a chosen chain but around a Chol molecule they were not. DMPC γ chains made closer contacts with Chol than the β chains.