The invention provides monoclonal antibody 3H6 and related antibodies. The 3H6 antibody binds to an epitope within residues 28-36 of IAPP. The antibodies of the invention are useful, for example, for treating disorders associated with IAPP accumulation, particularly accumulation of IAPP deposits. Such disorders include type 2 diabetes, metabolic syndrome, impaired insulin tolerance, impaired glucose tolerance, insulinomas, and related conditions.