A 3-yr-old, intact male Matschie's tree kangaroo (Dendrolagus matschiei) was examined for a 1-wk history of intermittent lethargy and tachypnea. An echocardiogram revealed concentric hypertrophy of the left ventricular free wall and interventricular septum. These findings were compared to measurements from healthy Matschie's tree kangaroos, supporting a diagnosis of hypertrophic cardiomyopathy. At the time of publication, the patient has been managed for over 11.5 yr, using a combination of enalapril, furosemide, diltiazem, and diet modifications. Hypertrophic cardiomyopathy should be considered as a differential diagnosis in tree kangaroos exhibiting signs of cardiovascular or respiratory distress. This case represents the first report of antemortem diagnosis and successful management of hypertrophic cardiomyopathy in a Matschie's tree kangaroo.