Amyloidosis is a disorder of protein folding in which normally soluble plasma proteins are deposited as insoluble fibrils that disrupt tissue structure. Over 20 unrelated proteins form amyloid in vivo, with fibrils sharing a cross-β-sheet structure composed of non-covalently associated protein or peptide subunits. Glycosaminoglycans and serum amyloid P component are universal non-fibrillar constituents of amyloid, contributing to fibrillogenesis and the stability of amyloid deposits. Amyloidosis may be acquired or hereditary and local or systemic, and is classified according to the precursor protein. Current treatment consists of support or replacement of impaired organ function and measures to reduce the production of amyloidogenic precursor proteins. Potential novel therapeutic strategies include stabilisation of the native fold of precursor proteins, reversion of misfolded proteins to their native state, inhibition of fibril propagation and enhancement of amyloid clearance either through immunotherapy or by reducing the stability of deposits through depletion of serum amyloid P component.