The present invention concerns methods and compositions of use for treatment of Alzheimer's Disease (AD). In certain embodiments, the methods concern preparation of phage-display single chain antibody libraries and screening against amyloid-beta (Aβ) protein or peptide. Anti-Aβ antibodies are selected and sequenced. In certain embodiments, synthetic Aβ binding peptides are designed and prepared, using portions of the anti-Aβ antibody sequences. The antibodies and peptides are of use for treatment of AD or for treatment of individuals at risk of developing AD. Compositions comprising anti-Aβ antibodies or Aβ binding peptides are also disclosed.