A 37-yr-old male vasectomized hybrid orangutan (Pongo pygmaeus × abelii) was diagnosed with left ventricular dysfunction during a preventative health care examination. Treatment was initiated with carvedilol. The following year, this orangutan was evaluated for intermittent lethargy. Following observation of an irregular cardiac rhythm during an echocardiogram, a lead II electrocardiogram revealed atrial fibrillation and ventricular arrhythmia. Additional treatment included amiodarone, furosemide, spironolactone, clopidogrel, and aspirin. An improved activity level was noted, and follow-up testing showed restoration of a sinus rhythm, reduced frequency of ventricular arrhythmia, and improved left ventricular function. The orangutan died 27 mon after initial diagnosis of heart disease, and a complete necropsy was performed. This article describes successful diagnosis and management of structural and arrhythmic heart disease in an orangutan, emphasizing the role of cardiac disease screening and behavioral training in apes, as well as the value of matching thorough antemortem and postmortem cardiac evaluation.