Summary. Thromboelastography (TEG) assesses the global pattern of blood coagulation in the whole blood. Present day management of haemophilia is based on replacement therapy with lost factor by parenteral administration of factor concentrates. It is very well known that interaction of cellular components in the blood also affect the thrombin generation which in turn might produce varied TEG patterns that might reflect the clinical severity in haemophilia patients. We evaluated 66 severe haemophilia A and B patients (as assessed by one-stage assay) by TEG and correlated the varied TEG patterns with the clinical severity in the patients. Four distinct TEG patterns were observed; Group A consisted of eight patients with hypercoagulable patterns while group B consisted of two patients showing hyperfibrinolytic patterns. Group C comprised of 17 patients whose TEG tracings did not show the initiation of clot formation at all while group D comprising of 39 patients showed varied clot initiation times ranging from almost normal pattern to a highly prolonged split times. Groups A and D patients were relatively milder clinically while groups B and C were clinically severe as assessed by the number of bleeding episodes, the frequency of transfusion and joint deformity. Subsequently we also evaluated the in vitro efficacy of the antifibrinolytic drug, EACA in normalizing the TEG patterns in 12 patients (group C) who did not show the initiation of clot formation in the TEG tracings to see the contribution of fibrinolysis in producing such patterns. The use of EACA in vitro in this group improved the TEG profile of these patients. In conclusion, the classification of severe haemophilia patients based on TEG patterns correlated well with the clinical severity and the ex vivo use of antifibrinolytics like EACA are effective in improving the TEG profile of all patients who had an abnormal TEG pattern without any clot initiation.