Aging is associated with a progressive dysregulation of immune responses. Whether these changes are solely responsible for the observed increased mortality and morbidity amongst the elderly is uncertain. Recent advances have highlighted the age-associated changes that occur beyond T and B lymphocytes. Additionally, multiple human and animal studies have identified a relationship between chronic low-grade inflammation and geriatric syndromes, such as frailty, suggesting that the phenomenon of "inflamm-aging" may provide a rationale for the increased vulnerability to chronic inflammatory diseases in older adults. In the present review, we broadly summarize our current understanding of age-dependent changes in leukocyte function and their contribution to aging-related disease processes.