Cytoskeletal proteins of the cultured fibroblasts obtained from Alzheimer's disease patients were studied. Western blotting studies of tubulin, actin, and vimentin showed no difference between Alzheimer and the control fibroblasts. Western blotting studies of vimentin revealed five partial degradation products in 50 K-57 K Da. molecular size region, but no difference in the degradation pattern was noticed between Alzheimer and the control fibroblasts. The size of fodrin molecule, however, was quite different between Alzheimer and the control fibroblasts. Comparing the molecular size of fodrin purified from the bovine brain, it is concluded that fodrin in Alzheimer fibroblasts is not degraded, while significant amount of fodrin in the control fibroblasts is partially degraded resulting in the smaller size of the 160 K and 200 K Da. molecular weight products.