Peak oxygen consumption (VO2peak), as measured by cardiopulmonary exercise testing (CPET), is a powerful independent predictor of cardiovascular disease (CVD) and all-cause mortality in a broad range of populations. We assessed the safety and feasibility of CPET in aging long-term hematopoietic cell transplantation (HCT) survivors, a population at high risk for premature onset of CVD. Next, we examined how organ-specific impairments (eg, cardiac, pulmonary, hematologic) impact VO2peak after HCT. Twenty consecutive HCT survivors underwent a comprehensive assessment of cardiopulmonary health that included CPET, echocardiography with strain, pulmonary function testing, 6-minute walk test, and timed up and go. Median age at assessment was 67.4 years (range, 42 to 75), and median time from HCT was 9.8 years (range, 3 to 20). No adverse events were observed during CPET procedures, and 95% of studies were considered to be at “peak” effort (respiratory exchange ratio ≥ 1.10). VO2peak was on average 22% less than predicted, and allogeneic HCT survivors had markedly lower VO2peak when compared with autologous HCT survivors (18.2 mL/kg/min versus 22.2 mL/kg/min; P = .05). Six participants (30%) had VO2peak ≤ 16 mL/kg/min, a threshold associated with a 9-foldrisk of death in patients undergoing HCT. Despite the presence of normal (>50%) resting left ventricular ejection fraction in all participants, 25% had markedly abnormal left ventricular longitudinal strain, an advanced echocardiographic measure of myocardial dysfunction. These findings highlight the role of stress-based measures and advanced myocardial imaging to characterize CVD risk in HCT survivors, setting the stage for tailored interventions to prevent CVD with its attendant morbidity and mortality.