To date, data regarding the efficacy and safety of administering fibrinogen concentrate in cardiac surgery are limited. Studies are limited by their low sample size and large heterogeneity with regard to the patient population, by the timing of fibrinogen concentrate administration, and by the definition of transfusion trigger and target levels. Assessment of fibrinogen activity using viscoelastic point-of-care testing shortly before or after weaning from cardiopulmonary bypass in patients and procedures with a high risk of bleeding appears to be a rational strategy. In contrast, the use of Clauss fibrinogen test for determination of plasma fibrinogen level can no longer be recommended without restrictions due to its long turnaround time, high inter-assay variability and interference with high heparin levels and fibrin degradation products. Administration of fibrinogen concentrate for maintaining physiological fibrinogen activity in the case of microvascular post-cardiopulmonary bypass bleeding appears to be indicated. The available evidence does not suggest aiming for supranormal levels, however.