Cardiac surgery with cardiopulmonary bypass (CPB) may lead to many postoperative complications. However, many complications cannot be predicted in time using the current clinical methods, or the prediction is not sufficiently accurate, resulting in a delay in treatment. Extracellular vesicles (EVs) are a group of membrane vesicles generated from various sources, including endothelial cells and platelets, upon activation or apoptosis. Here, we summarize the role of circulating EVs in predicting complications after cardiac surgery with cardiopulmonary bypass. We found that EV levels can predict acute heart failure. EV subtypes can predict acute heart failure, acute kidney injury, acute lung injury, blood transfusion, and neurological complications. The components of EVs can predict acute heart failure, acute kidney injury, acute lung injury, and neurological complications. The size distribution of EVs can predict acute lung injury. Therefore, circulating EVs can be used to predict complications after cardiac surgery with cardiopulmonary bypass.