The value of cardiovascular magnetic resonance (CMR) in assessing and predicting acute right ventricular (RV) dysfunction in patients with anterior ST-segment elevation myocardial infarction (STEMI) remains ascertained. Eightyeight patients with anterior STEMI were prospectively recruited and underwent CMR examinations within one week following the coronary intervention. Patients with RV ejection fraction (RVEF) less than 2 standard deviations below the average at the center (RVEF ≤ 45.0%) were defined as having RV dysfunction. The size of infarction, segmental wall motion, and T1 and T2 mapping values of global myocardium and the interventricular septum (IVS) were measured. Predictive performance was calculated using receiver-operating characteristic curve analysis and logistic regression test. Twentytwo patients presented with RV dysfunction. The RV dysfunction group had a larger IVS infarct extent (54.28 ± 10.35 vs 33.95 ± 15.09%, P < 0.001) and lower left ventricle stroke volume index (33.93 ± 7.96 vs 42.46 ± 8.14ml/m2, P < 0.001) compared to the non-RV dysfunction group. IVS infarct extent at 48.8% best predicted the presence of RV dysfunction with an area under the curve of 0.864. Left ventricular stroke volume index (LVSVI) and IVS infarct extent were selected by stepwise multivariable logistic regression analysis. LowerLVSVI (odds ratio [OR] 0.90; 95% confidence interval [CI], 0.79 to 0.99; P = 0.044) andhigher IVS infarct extent (OR 1.16; 95% CI 1.05 to 1.33; P = 0.01) were found to be independent predictors for RV dysfunction. In patients with anterior STEMI, those with larger IVS infarct extent and worse LV function are more likely to be associated with RV dysfunction.