Cardiac troponin assays have provided a significant contribution for the early diagnosis of cardiovascular events. There is significant evidence about the association between the absolute value of elevated cardiac troponin levels with the prognosis of patients with chest pain. However, it is well-known that elevated cardiac troponin levels may occur in situations other than acute coronary syndromes, as it happens with atrial fibrillation. The significance and prognosis of this elevation are not entirely clear. We review the evidence about the meaning of such elevation in the setting of atrial fibrillation.