Congential fibrinogen deficiency is a rare bleeding disorder caused by various mutations in three fibrinogen genes. It can be subdivided into four categories: afibrinogenemia, hypofibrinogenemia, hypodysfibrinogenemia and dysfbrinogenemia. This study was to elucidate the molecular defects in nine unrelated Chinese patients with hypofibrinogenemia or dysfibrinogenemia. Three fibrinogen genes were amplified by PCR and screened for variants. The identified variants were analyzed by bioinformatics prediction and molecular modeling analysis. Genetic screening disclosed seven different missense mutations, four of which were novel. All of the mutations were expected to impair the protein function/structure as assessed by bioinformatics prediction. This study has increased our knowledge of the mutational spectrum underlying fibrinogen deficiency.