Merrifield’s method for the synthesis of peptides on insoluble polymeric supports has been so successful that the great majority of peptides are now made using this technique. The advantages of Solid-Phase Peptide Synthesis (SPPS) over classical synthesis in solution are those of simplicity and speed of execution. SPPS is amenable to mechanization and has led to the development of automated peptide synthesizers5 that can be programmed to carry out the repetitive steps in the synthesis of a peptide. For a solid support to be useful in SPPS, certain properties are essential. It must consist of particles of a convenient size and shape that are physically robust enough to permit easy manipulation and rapid filtration from liquids. In SPPS, peptide amides have been obtained by ammonolysis of peptide–resins having ester anchorages to the solid support.