In observational studies of patients hospitalized for heart failure (HHF), risk of death is highest immediately after discharge and decreases over time. It is unclear whether this population risk trajectory reflects (1) lowering of individual patient mortality risk with increasing time from index hospitalization or (2) temporal changes in population case-mix with earlier postdischarge death for “sicker” patients. Survival rate and longitudinal models were used to estimate temporal changes in postdischarge all-cause mortality risk in 3,993 HHF patients discharged alive in the Efficacy of Vasopressin Antagonism in Heart Failure Outcome Study with Tolvaptan (EVEREST) trial. After median follow-up of 9.9 months, 971 patients died (24.2%). Predicted mortality rate decreased from 15.9 per 100 patient-years immediately after discharge to 13.4 at 30 days and 12.8 at 90 days; mortality rate increased steadily thereafter. Risk variation between quintiles of risk was considerably larger than the temporal variation within risk strata. In a longitudinal model serially reassessing predicted patient mortality risk after each follow-up visit using data collected at these visits, predicted mortality risk increased during the 90 days preceding subsequent heart failure readmission and then followed a postdischarge trajectory similar to the index admission. In conclusion, although there is transiently elevated individual patient risk in the 90 days before and after discharge, the patient's individual risk profile, rather than temporal change in risk relative to hospitalization, remains the main determinant of mortality. For purposes of reducing all-cause mortality in HF patients, preventative and therapeutic measures may be best implemented as long-term interventions for high mortality risk patients based on serial risk assessments, irrespective of recent hospitalization.