Aortic valve (AV) thrombosis is a rare but clinically significant condition with fewer than 80 cases of native AV thrombosis reported over the past 50 years. The clinical presentation varies widely, ranging from asymptomatic cases to acute myocardial infarction (MI), with or without cardiogenic shock. MI has been identified as the most common presentation and hypercoagulability as the most prevalent underlying etiology. Extracorporeal membrane oxygenation (ECMO) is a rare but documented cause of AV thrombosis due to the potential for clot formation in the setting of insufficient left ventricle (LV) offloading and decreased LV function. People with inherited thrombophilias and those on ECMO have an increased risk of developing thrombosis but via different mechanisms and in different settings. Diseases of hypercoagulability predispose the patient to venous thromboembolism (VTE) due to intrinsic blood abnormalities. Patients on ECMO face a risk of thrombosis due to mechanical challenges that can arise from the ECMO circuit itself and systemic inflammation. Transesophageal echocardiography (TEE) is the diagnostic modality of choice, which offers the highest sensitivity for detection of AV thrombus compared to cardiac computed tomography angiography or cardiac magnetic resonance imaging. While many interventions exist for the management of AV thrombosis, there are no current guidelines that outline the best treatment approach. Here we present a case of native AV thrombosis that developed in a patient on ECMO following an elective left heart catheterization (LHC). The patient suffered a series of complications that led to her requiring central veno-arterial (VA) ECMO when unable to be weaned from cardiac bypass. During evaluation for ECMO turndown via TEE guidance, the patient was found to have a large AV valve thrombus. Given the patient's extremely poor clinical prognosis, the decision was made to pursue a compassionate wean. Current interventions include anticoagulation, surgical thrombectomy, and systemic thrombolytics. However, a lack of randomized control trials outlining the best treatment approach remain unclear. While it may not be feasible given the critical nature of its presentation and rarity, further research is needed to guide the management of native AV thrombosis.