Great strides have been made in developing psychosocial interventions for the treatment of depression and bipolar disorder over the last three decades, but more remains to be done. The National Institute of Mental Health Psychosocial Intervention Development Workgroup recommends three priorities for future innovation: 1) development of new and more effective interventions that address both symptom change and functional capacity, 2) development of interventions that prevent onset and recurrence of clinical episodes in at-risk populations, and 3) development of user-friendly interventions and nontraditional delivery methods to increase access to evidence-based interventions. In each of these areas, the Workgroup recommends systematic study of the mediating mechanisms that drive the process of change and the moderators that influence their effects. This information will highlight the elements of psychosocial interventions that most contribute to the prevention and treatment of mood disorders across diagnostic groups, populations served, and community settings. The process of developing innovative interventions should have as its goal a mental health service delivery system that prevents the onset and recurrence of the mood disorders, furnishes increasingly effective treatment for those who seek it, and provides access to evidence-based psychosocial interventions via all feasible means.