Congenital dysfibrinogenemias are characterized by structural abnormalities in fibrinogen, which may lead to abnormal function. Fibrinogen has critical roles in coagulation, platelet aggregation and fibrinolysis; accordingly, abnormal fibrinogen function can result in a clinical phenotype, which varies from asymptomatic (around 55%) to bleeding (25%) and/or thrombosis (20%). We describe a novel γ326Cys→Phe mutation in the fibrinogen γ gene causing hypodysfibrinogenemia associated with life-threatening thrombosis in a family from Melbourne, Australia.