Human aging is reaching epidemic proportions as life expectancy increases and birth rate decreases. These demographic trends have led to a sharp increase in the diseases of aging, and an understanding of immune senescence promises to limit the development and progression of these diseases. In this review, we discuss three of the most important diseases of aging: shingles, Alzheimer's disease and atherosclerotic cardiovascular disease. All of these diseases have significant immunological components in either their etiology and/or progression, suggesting that appropriate immune intervention could be used in their prevention or treatment. Indeed, recent clinical studies have already demonstrated that vaccination can reduce the incidence of shingles and might prove effective in patients with Alzheimer's disease and artherosclerotic cardiovascular disease.