Depression is a disease affecting millions of people worldwide, has a high risk of recurrence and carries high health care and other societal costs. Prevention of depression is essential, in particular since depression is more likely to persist when no intervention is provided. In this chapter we discuss the prevention framework developed by the Institute of Medicine (IOM) for providing a model to understand the different objectives of interventions. We also discuss risk factors specific for the elderly and identification of the population at risk. Finally we review some best practices in depression interventions and offer some suggestions for future research.