Hyperpolarized 129Xe MRI/MRS is a rapid and non-invasive tool with significant potential to evaluate the causes of dyspnea. 129Xe, once inhaled, freely diffuses from the airspaces, across the interstitial barrier tissues, and into the pulmonary capillaries, with distinct spectral peak in each of these compartments. In a single breath hold, this enables separate imaging and spectral characterization of the ventilated 129Xe distribution in the airspaces, its uptake in lung parenchyma (barrier), and transfer to red blood cells (RBCs). These 3D images are transformed into quantitative maps that report on the severity and spatial heterogeneity of pulmonary disease as it affects the airspace, interstitial, and pulmonary vascular compartments. Such imaging can be coupled with 129Xe dynamic MR spectroscopy (MRS), which reveals cardiogenic variations of 129Xe transfer to the capillary RBCs that can differentiate pre- and post-capillary pulmonary hypertension (PH). Through these unique properties, 129Xe MRI reports both on pulmonary gas exchange and variation in capillary blood volume, providing a detailed assessment of lung disease as well as the potential presence of pre- or post-capillary PH. This chapter will briefly describe the key technical properties, and discuss current and future applications and opportunities for 129Xe MRI pulmonary imaging.