The Heart Failure Survival Score (HFSS) and peak exercise oxygen consumption (Vo₂) accurately assess mortality in ambulatory patients who have advanced heart failure and are referred for initial cardiac transplant evaluation. We investigated the prognostic value of the HFSS and peak Vo₂ when applied serially to these patients. This study included 227 adults (mean age ± SD 52 ± 10 years old) who presented for reevaluation >60 days after initial evaluation (352 ± 238 days). The HFSS was determined from mean arterial blood pressure, heart rate, left ventricular ejection fraction, serum sodium, peak Vo₂, heart failure etiology, and width of QRS complex. Survival without reevaluation, United Network of Organ Sharing 1 transplant, or left ventricular assist device was determined by the Kaplan-Meier method with censoring at United Network of Organ Sharing 2 transplant. Survival differed by HFSS stratum (p <0.001) and by peak Vo₂ stratum (p <0.001). Patients whose HFSS or peak Vo₂ deteriorated from low risk to medium or high risk had lower survival rates than did patients whose values remained at low risk (p <0.01 and p <0.001, respectively). Patients who started at medium or high risk and improved to low risk tended to have higher survival rates than those who remained medium or high risk (p = 0.06 and p <0.16, respectively). Patients who improved to low risk had a 1-year survival rate of 72% for HFSS and peak Vo₂. However, patients who improved to low risk and were treated with β blockers had a 1-year survival rate (89% for HFSS and 83% for peak Vo₂) comparable to that after transplant (84%). Peak Vo₂ and the HFSS can be successfully used for serial evaluation of mortality risk in ambulatory patients who have advanced heart failure.