Thirteen patients with renal carcinoma were examined for tumour-directed, cell-mediated hypersensitivity (TCMH) by means of the leucocyte migration technique, and for general immunocompetence (GIC) by means of quantitation of T- and B-cells in peripheral blood and studies of lymphocyte transformation in vitro using a panel of antigens and mitogens. Eight out of 13 patients had evidence of TCMH, six out of 13 had abnormal GIC. Any correlation between the presence of TCMH and normal/abnormal GIC was not found. There was a trend towards a positive correlation between the absence of distant metastases and evidence of TCMH. If both TCMH and GIC were considered, significant correlation between the presence of distant metastases, lack of TCMH and/or abnormal GIC was demonstrated. It is concluded that the defect TCMH usually found in patients with renal carcinoma and disseminated disease cannot be explained exclusively by defects in GIC.