Does chronic illness in older people provide potentials for human development? To date, this question has not been adequately addressed by dynamic theorists of human development. In this article, two illness trajectories, Alzheimer's disease and stroke, are examined to illustrate emerging changes in human development over each course of illness and the increasing importance of attachment behavior among ill elders and their family members. It is argued that the phenomenon of attachment links ailing older people to their environment, and that attachment is vital if human development is to continue.