We show a significantly decreased number of OKT3+ lymphocytes in the peripheral blood (PB) of cancer patients mainly due to a reduced number of OKT4 cells. OKT8 cells were also somewhat reduced. The numbers of DR+ and interleukin-2 receptor-bearing T-cells were significantly increased in patients. The tumor-infiltrating cells included OKT4+ AND OKT8+ lymphocytes. There was a significant correlation between the proportion of activated T-cells in PB and in tumor, as shown by DR and interleukin-2 receptor expression.