The term nonbacterial thrombotic endocarditis (NBTE), or marantic endocarditis, refers to a spectrum of lesions ranging from microscopic aggregates of platelets to large vegetations on previously undamaged heart valves (most often aortic and mitral) in the absence of a bloodstream bacterial infection. NBTE is a rare condition often associated with hypercoagulable states or advanced malignancy such as adenocarcinomas. In this article, the pathogenesis, incidence, clinical manifestations, diagnosis, and management of NBTE in cancer patients are reviewed.