Abstract: The present invention is directed to methods and kits for diagnosing, Alzheimer's disease. The invention is based, in part, on the discovery that proteolytic fragments of the amino and carboxy terminal amino acid residues of tau-proteins are released from the neurofibrillary tangles associated with the disease and can be detected in body fluids outside the brain. The tau-proteins will be purified or chemically synthesized and peptide fragments of the amino terminal and carboxy terminal regions will be obtained proteolytically or synthesized chemically and will be used in generating tau specific antibodies for use in diagnostic kits for the detection of Alzheimer's disease. These diagnostic kits will be used in screening the body fluids of individuals for the presence of tau-peptide fragments. Alternatively, the tau-peptides themselves may be used in diagnostic kits for screening the body fluids of individuals for the presence of circulating autoantibodies.