The relation between the etiology of cardiomyopathy and the function of the right ventricle (RV) has not been well described in the current era of 3-dimensional cardiac imaging. New advances in cardiac imaging with computed tomography (CT) have allowed accurate measurements of ejection fraction (EF), often a challenging task considering the unique RV shape. We evaluated 130 patients at the Loma Linda Veterans Affairs Healthcare System with cardiomyopathy and a left ventricular (LV) EF ≤ 40%. Etiology of cardiomyopathy was determined by CT angiography as ischemic (n = 56) or nonischemic (n = 74). RV volumes and RVEF were calculated based on 3-dimensional data set from CT images. Baseline LVEF was similar with a mean LVEF of 28% (± 6%) in the ischemic group and 28% (± 9%) in the nonischemic group (p = 0.46). RV function and volumes were moderately decreased in both cohorts, without significant difference between the groups (mean RVEF 34 ± 11% in ischemic group and 32 ± 10% in nonischemic group, p = 0.26). In conclusion, most patients with LV dysfunction also have RV dysfunction. The degree of RV dysfunction is not dependent on the etiology of cardiomyopathy.