Left ventricular (LV) thrombus is a feared complication of LV dysfunction due to substantial rates of associated morbidity and mortality. Identification is critical in order to prevent potentially devastating sequelae of embolization. Two-dimensional transthoracic echocardiography is the diagnostic modality most commonly used to identify an LV thrombus. The typical sonographic appearance of an LV thrombus is an echodense mass adherent to the endocardium with distinct margins and independent motion. LV thrombi are often found in proximity to segmental hypokinesis, akinesis, or LV aneurysm. LV thrombi may be distinguished by morphologic features including mural, protruding, and mobile variants which have variant-specific risks of embolization. The application of ultrasound-enhancing agents (UEAs) with the goal of left ventricular opacification (LVO) improves the ability of echocardiography to identify LV thrombi and distinguish a thrombus from anatomic structures. If the ultrasound diagnosis of LV thrombus is uncertain, cardiac magnetic resonance imaging (CMR) should be considered given greater diagnostic accuracy. Guidelines recommend the use of anticoagulant therapy for at least 3 months duration for the treatment of LV thrombus.