Religiousness (typically assessed as service attendance) is often associated with well-being and psychological distress in persons with life-threatening illnesses, but little of this work has focused explicitly on religious beliefs. We examined the longitudinal relationships of religious beliefs (i.e., in God and in the afterlife) with well-being and distress (assessed 6 months later) in a sample of patients with congestive heart failure, a chronic and progressive disease. After controlling for religious service attendance, belief in God was associated with negative affect and spiritual well-being, while belief in the afterlife was associated with physical health, post-traumatic depreciation, and spiritual well-being. However, after controlling for baseline values of well-being or distress, religious beliefs were not associated with nearly all well-being or distress outcomes at follow-up. Over the 6-month duration of the study, participants increased in belief in afterlife but decreased in their belief in God. Increases in religious beliefs across time were associated with higher levels of distress. These results suggest that religious beliefs are neither positively nor negatively associated with well-being and distress independent of religious attendance among seriously ill patients with CHF. Based on these findings, healthcare providers are encouraged to assess religious belief change at the individual level to better understand and inform spiritual care for patients with late-stage CHF.