129Xe MRS has the potential to detect and characterize cardiopulmonary disease; however, clinical use demands a better understanding of the repeatability of these measurements. We studied the within-session repeatability of 129Xe MR static and dynamic spectroscopy of 117 pairs of scans with matched heart rates and adequate quality in both scans. Repeatability of each spectroscopic measurement was quantified using the coefficient of repeatability (CR), coefficient of variation (CV), and the intraclass correlation coefficient (ICC). All measurements had very little bias between the two scans and significant ICCs. The CRs for RBC:barrier and RBC amplitude oscillation were 0.07 and 4.2%, respectively.