To examine (1) advanced congestive heart failure (CHF) patients' estimates of their longevity and changes in these estimates over time; (2) clinical, functional, and psychological adjustment correlates of these longevity estimates; and (3) correspondence of changes in longevity and changes in multiple dimensions of spirituality over time. Longitudinal questionnaire-based study of 111 patients diagnosed with severe CHF assessed at two time points separated by 6 months. Nearly half of the participants estimated their longevity as at least 5-10 years, and there was very little change in estimates across the assessment periods. Longevity estimates were minimally related to clinical or functional indicators, but longer estimates were related to fewer depressive symptoms and higher levels of life satisfaction. Multivariate regression analyses indicated that shifting longevity estimates toward less time or toward uncertainty was related to increases in religious life meaning and forgiveness and to decreased spiritual struggle over the 6-month interval. No effects were observed for daily spiritual experiences. Because very little is known about how individuals estimate their remaining life span, these results establish information regarding their basis (i.e., not clinical or functional) and stability, at least in the context of advanced heart failure. In addition, the notion that individuals become more spiritual as they perceive the approach of death was borne out in terms of multiple aspects of spirituality.