We conducted a multicentre study of 101 subjects with Congenital Dysfibrinogenemia (CD) to characterize the incidence of hemorrhagic and thrombotic events as well as complications of pregnancy and surgery. At the time of diagnosis, 10.9% and 13.9% had experienced major bleeding and thrombotic events, respectively. During a mean follow-up of 8.8 years after CD diagnosis, the incidence of major bleeding and of thrombotic events was 2.5 and 18.7 per 1000 patient-years respectively, with estimated cumulative incidences at an age of 50 years of 19.2% and 30.1%. We identified 111 pregnancies with an overall incidence of spontaneous abortions and post-partum hemorrhage of 19.8% and 21.4%, respectively. The risk of post-partum hemorrhage was associated with a previously identified bleeding phenotype (OR 5.8; 95%CI 1.2-28.0). Among 137 surgical procedures analyzed, 9 (6.5%) were complicated by abnormal bleeding. Propositi versus relatives, sex, mutation hotspots, fibrinogen levels and activity:antigen ratios were not associated with the risk of thrombotic or bleeding outcomes. In conclusion, the results of our study, the largest in genotyped CD and the first including long term history, indicate that propositi with CD and their relatives carry not only a high risk of major bleeding, including post-partum hemorrhage, but also of thrombotic event.