Sudden cardiac death (SCD), presumed secondary to fatal arrhythmias, is a common cause of mortality in captive chimpanzees at the Alamogordo Primate Facility. Over the 6-year period at the Alamogordo Primate Facility between 2001 and 2006, 13 animals were defined as sudden cardiac death (11 male and 2 female) on the basis of clinical presentation which was 38% of all deaths. All animals had annual physical exams, including electrocardiograms and serial blood pressures. Six of the 13 animals underwent a complete cardiac evaluation by a veterinary cardiologist and all six of these animals were diagnosed with various degrees of cardiomyopathy. Systemic hypertension was noted in two of the 13 cases and antemortem cardiac arrhythmias were seen in all 13 animals. Histological examination of the hearts revealed myocardial fibrosis in 12 chimpanzees. Most of the animals (10/13) that died of sudden cardiac death had cardiomegaly (increased heart weight/body weight ratio) and some degree of myocardial fibrosis noted. Additional data as well as serial diagnostic evaluations will be needed to identify the possible causes of sudden cardiac death in captive chimpanzees.