Background-Cardiovascular magnetic resonance is the gold-standard technique for the assessment of ventricular function.Although left ventricular volumes and ejection fraction are strong predictors of outcome in dilated cardiomyopathy (DCM), there are limited data regarding the prognostic significance of right ventricular (RV) systolic dysfunction (RVSD). We investigated whether cardiovascular magnetic resonance assessment of RV function has prognostic value in DCM. Methods and Results-We prospectively studied 250 consecutive DCM patients with the use of cardiovascular magnetic resonance. RVSD, defined by RV ejection fraction ≤45%, was present in 86 (34%) patients. During a median follow-up period of 6.8 years, there were 52 deaths, and 7 patients underwent cardiac transplantation. Received March 10, 2013; accepted July 30, 2013. From the Royal Brompton Hospital, London, United Kingdom (A.G., T.F.I., A.J., F.A., K.G., N.A.I., S.R., J.K., T.D.H.B., K.M., E.L., M.R., R.W., T.C.P., R.S., J.-P.C., S.A.C., M.R.C., R.G.A., D.J.P., S.K.P.); Ealing Hospital, London, United Kingdom (R.G.A.); National Heart & Lung Institute, Imperial College, London, United Kingdom (T.F.I., K.G., R.S., J.-.P.C., S.A.C., M.R.C., D.J.P., S.K.P.); and National Heart Centre Singapore, Singapore (S.A.C.).The online-only Data Supplement is available with this article at http://circ.ahajournals.org/lookup/suppl