Stress and psychosocial resources play a crucial role in late-life depression. While most studies focus on predominantly those who are young-old, this study used a sample aged 85 and older. The authors' study aims to examine three research questions: (1) What are the trajectories of depression and its associated factors such as types of stress and psychosocial resources among the oldest-old? (2) What are the longitudinal relationships among the changes in stress, psychosocial resources, and depressive symptoms? (3) Are the effects of the changes in stress on depression trajectory mediated by changes in psychosocial resources? The study used a convenience sample of 193 community-dwelling elders aged 85 and older with four interviews every six months from 1986 to 1988. Using multilevel modeling analyses, longitudinal results showed that changes in positive life events, daily hassles (worries), and mastery were significantly associated with changes in late-life depression among the oldest-old.