Canine hyperadrenocorticism, a prevalent endocrine disorder characterized by excessive cortisol production. Notably, hypercoagulability leading to pulmonary thromboembolism (PTE) poses a substantial concern. PTE may be underestimated because of the rapid dissolution of canine thrombi postmortem. However, traditional coagulation assays face challenges in early detection of hypercoagulability. Therefore, this study explored the use of thromboelastography (TEG) as a diagnostic tool for identifying hypercoagulability in dogs with hyperadrenocorticism. A total of 31 dogs visited the Gyeongsang Animal Medical Center between 2018 and 2022, comprising 21 dogs with hyperadrenocorticism and 10 controls who underwent clinical and coagulation analyses. Hyperadrenocorticism was diagnosed using a low-dose dexamethasone stimulation test or adrenocorticotropin hormone stimulation test, and conventional laboratory parameters and coagulation parameters, such as the prothrombin time, activated partial thromboplastic time, fibrinogen, and TEG results, were compared between the groups. Clinical data revealed significantly elevated monocyte, platelet, alanine aminotransferase, alkaline phosphatase, triglyceride, and cholesterol concentrations in dogs with hyperadrenocorticism, which were attributed to excess cortisol secretion (p<0.05). TEG analysis demonstrated significantly decreased K values and increased α and MA values in hyperadrenocorticism dogs (p<0.05), indicating a shortened clotting time and enhanced clot strength, suggestive of hypercoagulability. TEG effectively highlights hypercoagulability in dogs with hyperadrenocorticism and provides valuable insights in predicting blood clot formation. Although predicting clot formation in dogs remains complex owing to multifactorial influences, this study underscores the potential utility of TEG in enhancing such predictions for dogs with hyperadrenocorticism.