We have developed a simple method for isolation of functionally active T cell receptor (TCR)-gamma delta positive cells from human peripheral blood, using immunomagnetic separation techniques. After culture with feeder cells and interleukin-2, cells thus isolated showed a CD3+ TCR-alpha beta- phenotype, and stained with antibodies against the TCR-gamma delta complex. The TCR-gamma delta+ cells were functionally active, responding with DNA synthesis when stimulated via their CD3 and CD2 molecules in concert, or when interleukin-2 was added.