As rates of depression have increased, there has been an increasing focus on the prevention and relapse prevention of depression. Concurrent with these efforts, there has also been an emphasis on identifying specific risk factors involved in the onset of depressive symptomatology. The current project draws on recent research in the self literature to prospectively identify a risk model of depression. Utilizing a daily diary methodology over a period of one month, it was hypothesized that persons who had contingently based sources of self-worth would be at risk for self-definition and mood lability when they experienced stressful life events. In turn, it was anticipated that these changes would predict an increase in self-reported depressive symptoms. The results demonstrated that persons with high contingent self-esteem, when they encountered stressful life events, had greater negative change in their self-concept clarity, and had greater lability and overall level of daily negative mood. In turn, decreases in self-concept clarity over time predicted a prospective increase in depressive symptomatology. The implications of these results for future research and clinical practice are discussed.