A new case of dysfibrinogenemia is reported which shows no signs of a haermorrhagic diathesis (dysfibrinogenemia Giessen III). The abnormal fibrinogen was detected by only slight but characteristic alterations of some parameter of the coagulation analysis (prolonged clotting times after addition of thrombin, Reptilase and thrombin coagulase; low fibrinogen concentration determined by methods based on clot formation in comparison to the immunological fibrinogen determination; delayed fibrin polymerization). In addition, clinical features and diagnosis of dysfibrinogenemia are described in general.