Until recently, plaque formation was considered to be the only determinant of atherosclerotic luminal narrowing. Recent post-mortem and intravascular ultrasound studies, however, revealed that arterial remodelling is another important determinant of luminal narrowing in de novo atherosclerosis. The change in total arterial circumference relative to a reference cross-section ranges from excessive enlargement with an actual increase in lumen to arterial shrinkage contributing to lumen narrowing. The mechanisms responsible for this spectrum of remodelling are unknown, but their identification will be important for the potential development of therapeutic strategies to promote favourable remodelling.