This paper focuses on relational exclusion (i.e. isolation and non-participation in social activities) in very old age. Based on a five-year study of an octogenarian cohort, the authors investigate the impact of three critical life events (deterioration of health, death of a close relative, entry into a nursing home) on relational life and social involvement. With advancing age, older people withdraw from some social activities, but their relationships with their family and friends remain stable. Life events have a stimulative effect on the support network (especially of family), and only the deterioration of health curbs social activity. This would seem to confirm the existence of a process of disengagement stemming more from the older people's functional or sensory disabilities than from an individual choice.