Objective: The aims of the study were to assess the performance of cardiac magnetic resonance (CMR)-derived cardiac chamber volumes and volume ratios to identify group 2 pulmonary hypertension (PH) patients and to determine their cutoff values with the highest sensitivity and specificity. Methods: One hundred six patients underwent CMR, 2 months after the diagnosis of PH by right heart catheterization. We classified patients with pulmonary capillary wedge pressure of greater than 15 mm Hg as group 2 PH. Cardiac chamber volumes indexed to the body surface area and volume ratios were correlated to the type of PH. Their sensitivity and specificity to detect group 2 PH were examined at various cutoff points. Results: The most appropriate cutoff values to designate group 2 PH patients with high sensitivity and specificity were as follows: left atrium volume index of 54.72 mL/m or greater, right ventricle volume/left atrium volume of 2.07 or less, and right atrium volume/left atrium volume of 1.61 or less. Conclusions: Cardiac magnetic resonance-derived cardiac chamber volume indices and volume ratios can determine group 2 PH diagnosis with high sensitivity and specificity.