A family with two complex disorders of hemostasis, von Willebrand disease (vWD) and hypofibrinogenemia was reported. The probands were 21- and 16-year-old full brothers suffering from serious bleeding tendencies from childhood. The elder brother had a subarachnoid hemorrhage at the age of 15. The younger brother had repeated episodes of gastrointestinal bleedings since he was 10 years of age. Coagulation studies revealed that both of them had almost the same hemostatic abnormalities, i.e. severe vWD, 9 to 12% of plasma vWF levels, and mild hypofibrinogenemia, 125 to 130 mg/dl of plasma fibrinogen levels. Multimeric compositions of their vWF were normal, and functional assay for fibrinogen concentration yielded essentially the same values as did immunologic assay. These results indicated that they had two complex disorders, extreme type I vWD and heterozygous state of afibrinogenemia resulting in serious bleeding tendency. Family study showed that these two hemostatic disorders were paternal inheritance, and it was strongly postulated that vWD and hypofibrinogenemia might be highly-combined hemostatic disorders.