In late life, depression is the most prevalent functional psychiatric disorder. Because the presentation may be multicausal and clinically complex, early assessment of biologic and psychosocial factors, diagnosis, and appropriate referral are important in ameliorating the associated morbidity and mortality. Nurses must have current knowledge and skills to assess mood states of elderly persons and to implement appropriate interventions. Successful management of depression in the elderly results in a reformulation of purpose and an enhanced quality of life.