We have previously reported that a subset of T cells in T cell receptor (TCR)‐transgenic mice may express two different α chains on their surface. The expression of two functional α chains has also been demonstrated for human peripheral blood T cells. In this report, we show that a proportion of normal murine lymph node T cells express two functional α chains on their surface. The extrapolated frequency of these cells present in the normal repertoire ranges from 7–21%, with an average of 15%. Our analysis of a small number of antigen‐specific T cell clones suggests that the frequency of antigen‐responsive cells expressing two surface α chains is relatively low. This raises the possibility that dual α chain T cells may have a selective disadvantage in responding to specific antigen.