Atherosclerosis is now considered a systemic inflammatory disorder affecting the arterial tree. Inflammation plays a role in all stages of the disease, from the initiation of the fatty streak to the final stage of plaque rupture. Atherosclerotic plaques that demonstrate the features of active inflammation are more likely to become symptomatic. In addition to having a higher risk of developing adverse cardiovascular events, patients who have higher indices of inflammation may be more likely to develop restenosis after endovascular stenting. Thus, the identification of the 'inflamed plaque' is the subject of intense research. The detection of the inflamed plaque by the conventional modalities of ultrasound, magnetic resonance imaging, computed tomography and nuclear medicine as well as the novel imaging modalities of optical coherence tomography, near-infrared spectroscopy, thermography and angioscopy will be examined.