The immunohistochemical findings in the kidneys of two sisters with homozygous familial amyloidosis of Finnish type, an autosomal dominant disorder of gelsolin catabolism, is described. The disease, manifesting with nephrotic syndrome and end-stage renal failure was characterized by heavy glomerular deposits of gelsolin-derived amyloid. Immunostaining also revealed the presence of gelsolin in the tubular epithelium that was Congo-red negative. It is concluded that homozygous Finnish amyloidosis leads to a severe nephropathy due to the deposition of fragments of mutant gelsolin.