Aging in humans is associated with progressing decline in T cell numbers and functions. In addition, there is an increased production of tumor necrosis factor-alpha (TNF-alpha) during human aging. TNF-alpha mediates both survival and cell death signals. TNF-alpha exerts its biological effects via TNFR-I and TNFR-II. Here we discuss signaling pathways induced by TNF-alpha and the effect of age on TNF-alpha-induced apoptosis in T cells and T cell subsets. T cells and T cell subsets from aged humans are more sensitive to TNF-alpha-induced apoptosis, which appears to be due to both an increased apoptotic signaling and decreased survival signals.