On deletion of the gene encoding the constant region of the T cell antigen receptor (TCR)α chain in mature T cells by induced Cre-mediated recombination, the cells lose most of their TCR from the cell surface within 7–10 days, but minute amounts of surface-bound TCRβ chains are retained for long periods of time. In a situation in which cellular influx from the thymus is blocked, TCR-deficient naïve T cells decay over time, the decay rates being faster for CD8⁺ cells (t_1/2 ≈ 16 days) than for CD4⁺ cells (t_1/2 ≈ 46 days). TCR⁺ naïve cells are either maintained (CD8⁺) or decay more slowly (CD4⁺; t_1/2 ≈ 78 days.) Numbers of TCR-deficient memory T cells decline very slowly (CD8⁺ cells; t_1/2 ≈ 52 days) or not at all (CD4⁺ cells), but at the population level, these cells fail to expand as their TCR⁺ counterparts do. Together with earlier data on T cell maintenance in environments lacking appropriate major histocompatibility complex antigens, these data argue against the possibility that spontaneous ligand-independent signaling by the αβTCR contributes significantly to T-cell homeostasis.