Fibrinogen is a natural blood protein involved in the coagulation process. Bleeding decreases the blood level, and low levels of this protein may increase bleeding even further, thereby increasing morbidity and mortality. Fibrinogen concentrate is widely used instead of traditional sources of fibrinogen, such as the blood products fresh frozen plasma and cryoprecipitate (a pooled concentrated plasma product), especially in some countries, despite the lack of adequate knowledge derived from previous research to support such an approach. In the present Cochrane systematic review, we set out to assess the benefits and harms of fibrinogen concentrate in patients with bleeding. We searched the databases to August 2013, we identified six randomized trials in cardiac and elective surgical settings that compared fibrinogen concentrate (248 participants) with placebo/other sources or no treatment. Additionally, we found 12 ongoing trials, but we were unable to retrieve any data from them. We could not identify beneficial effects of fibrinogen concentrate on patient survival. In our predefined outcomes, we identified a reduced proportion of patients requiring donor blood transfusion. We could not identify reduced blood loss or any harms or adverse events caused by treatment with fibrinogen concentrate. However, all trials were of low quality and were small, so evidence in support of fibrinogen concentrate in patients with bleeding remains weak.