Sarcoidosis is an inflammatory, granuloma-forming disease of unclear origin, mainly characterized by the involvement of the lungs and mediastinal lymph nodes. Cardiac involvement is found in 10–25% of all sarcoidosis patients and can also occur in isolation in individual cases. Since the occurrence of cardiac sarcoidosis has a significant impact on the morbidity and mortality of the affected patients, the early diagnosis of cardiac involvement is of decisive therapeutic and prognostic importance. The detection of myocardial damage by the presence of “late gadolinium enhancement” (LGE) in cardiac magnetic resonance imaging (cardiac MRI) and the nuclear medical detection of active myocardial inflammation can make an important contribution to diagnosis and risk stratification. Involvement of the left ventricular myocardium and the conduction system is predominant, so affected patients often clinically present with arrhythmias and/or heart failure symptoms. Although corticosteroids have been the first-line drug therapy for years, the therapy of cardiac sarcoidosis is not sufficiently standardized due to a lack of larger, randomized studies.