This paper identifies the components of a successful wellness-illness transition on the experience and management of depression. Data collection and analysis were informed by Corbin and Strauss' approach to grounded theory. Exemplars and case studies are used to illustrate the findings. Three themes reflected participants' experiences of a wellness-illness transition relating to depression in older adults: Accepting a change in wellness-illness status, Adapting to the changeable nature of depression, and Creating new meaning. A change in wellness-illness status is interpreted through personal beliefs about depression, and the knowledge, skills and resources required to optimise well-being. Successful transitions were associated with improved experience and management of depression. The findings have implications for how older adults recognise and respond to symptoms of depression. Judicious advice and support from health professionals can facilitate wellness-illness transitions, thereby enhancing health and well-being outcomes for older adults with depression.