The objective of this study is to report the use of thromboelastography as a diagnostic tool for the hyperfibrinolytic phase of disseminated intravascular coagulopathy in a dog with metastatic haemangiosarcoma. We established a cytological (i.e. fine needle aspirate) and histopathological (i.e. excisional surgical biopsy) diagnosis of haemangiosarcoma in a 10-year-old male castrated Bichon Frise with multiple dark purple dermoepidermal nodules on the ventral abdomen and medial stifle areas, multiple small pulmonary nodules and a solitary liver mass. The dog was treated with chemotherapy (AC protocol). Forty-nine days after completion of four treatment cycles, the dog was presented for recheck. Complete blood count revealed anaemia and mild thrombocytopenia. Chemistry profile showed no significant abnormalities. Analysis of haemostasis consisted of prolonged clotting times (prothrombin time, activated partial thromboplastin time), mild hypofibrinogenaemia and increased D-dimers. A presumptive diagnosis of disseminated intravascular coagulopathy was made. A re-calcified thromboelastography was simultaneously done to confirm the coagulopathy. Thromboelastographic tracings correlated with the plasma-based test results showing hypocoagulability (prolonged clotting times and prolonged thromboelastography clot kinetics; weaker clot with decreased fibrinogen levels, platelet count and lower thromboelastography tracing amplitude) and hyperfibrinolysis (increased D-dimers and increased D-dimers and increased thromboelastography lysis parameters). Based on these results, the dog was considered to be in the hyperfibrinolytic phase of disseminated intravascular coagulopathy. Results of the conventional haemostasis tests supported those obtained on thromboelastography. Humane euthanasia was performed because of poor prognosis and progressive disease, making further follow-up unavailable. As demonstrated in this case report, thromboelastography was found to be a helpful diagnostic tool for the diagnosis and monitoring of the hyperfibrinolytic phases of disseminated intravascular coagulopathy.