Expression of CD4 or CD8 on the cell surface is an important guide for discriminating the immunologic functions of T-cells. However, a minor T-cell subset lacking both CD4 and CD8 molecules but bearing the usual form of T-cell receptor (TCR)-alpha beta (CD4-CD8-TCR-alpha beta+ T-cells) has recently been found not only in mice but also in humans, and the clinical relevance of this newly defined subpopulation to human diseases is now of considerable interest. The authors present a patient in whom CD4-CD8-TCR-alpha beta+ T-cells showed monoclonal proliferation in the peripheral blood for more than 3 years, then disappeared spontaneously, followed by subsequent development of Hodgkin's disease. The pathologic roles of double-negative T-cell proliferation in this case are discussed from the viewpoint of premalignancy in lymphoproliferative diseases.