Résumé : Background: In humans, a high concentration of adiponectin is associated with a favorable cardiovascular risk profile whereas, in patients with heart failure (HF), a high concentration of adiponectin is associated with a less favorable prognosis. Hypothesis/Objectives: To evaluate the physiological determinants of plasma adiponectin concentration in dogs and the influence of heart disease, myxomatous mitral valve disease (MMVD), and dilated cardiomyopathy (DCM). Animals: One hundred and fourteen client-owned dogs and 9 Beagles from the research colony of the Clinical Veterinary Unit of the University of Liège. Methods: We prospectively measured circulating adiponectin concentration in healthy control dogs (n = 77), dogs with MMVD (n = 22) and dogs with DCM (n = 15) of various degrees of severity. Diagnosis was confirmed by Doppler echocardiography. Plasma adiponectin concentration was measured by a canine-specific sandwich ELISA kit. Results: An analysis of covariance showed an association between adiponectin concentration and age, neuter status, and heart disease. No association between adiponectin concentration and class of HF, sex, body condition score, body weight, circadian rhythm, or feeding was found. Plasma adiponectin concentration was negatively correlated with age (P =.001). Adiponectin was lower in neutered (P =.008) compared to intact dogs. Circulating adiponectin concentration was increased in dogs with DCM compared to healthy dogs (P =.018) and to dogs with MMVD (P =.014). Conclusions and Clinical Importance: Age and neutering negatively influence circulating adiponectin concentration. Plasma adiponectin concentration increased in dogs with DCM. Additional research is required to investigate if this hormone is implicated in the pathophysiology of DCM and associated with clinical outcome.