Libman–Sachs endocarditis (nonbacterial thrombotic endocarditis, NBTE) may be one of the cardiac manifestations of systemic lupus erythematosus (SLE). It is characterized by the presence of sterile platelet thrombi on previously normal heart valves. The diagnosis of NBTE is difficult as it is often asymptomatic until complications such as systemic emboli or valvular dysfunction occur. Patients with Libman–Sachs endocarditis and SLE are treated with immunosuppressive and anticoagulant therapy and, if it is ineffective, surgical treatment.A clinical case of SLE and Libman–Sachs endocarditis is presented. The clinical manifestations, diagnostic methods and treatment of NBTE in SLE are discussed. The difficulties in differential diagnosis and selection of optimal treatment tactics faced by physicians are highlighted.