About 4% of human T cells carry antigen receptor composed of gamma and delta chains (rather than alpha and beta chains). Double immunoenzymatic staining of frozen sections of 14 samples of human spleen showed that gamma delta bearing T cells were preferentially localised in the red pulp of this organ where on average they accounted for 17% of all T cells. There was no correlation between the number of gamma delta T cells and the diagnosis, with the exception of a case of malaria in which an unusually high number (40%) of T cells were of this type. The gamma delta bearing T cells were scattered randomly through the red pulp, and double staining combined with a marker of splenic sinusoids (CD36) showed that almost all lie outside the sinusoids within the cords of the red pulp. It is suggested that the double immunoenzymatic technique could be used for further studies of the prevalence of gamma delta bearing T cells in lymphocytic infiltrates.