Kidneys of 27 consecutive autopsied patients with bronchogenic carcinoma without clinical renal disease were studied by electron microscopy and immuno-histochemistry for the presence of glomerular deposits. Two patients had subepithelial electron-dense deposits compatible with immune complexes but failed to stain histochemically for immunoglobu-lin; most cases (19 of 27). including the two with complexes, demonstrated subendothelial deposition of fibrin. No tissue samples had histochemically detectable immunoglobulin. From this study it is suggested that renal immune complexes in lung cancer are rare.