Peptides are an important class of Active Pharmaceutical Ingredients. Indeed, it is now feasible to synthesize peptides of up to forty amino acids in a multi-kilogram scale. This achievement has been made thanks to the implementation of the solid-phase synthesis methodology described by the Nobel Laureate R. Bruce Merrifield in 1963. Successful solid-phase peptide synthesis depends directly on the quality of the polymeric support, namely the resin. Here we describe new polystyrene in-house resins produced by 'Jetting' technology. The excellent properties (swelling, loading, particle size distribution, morphological structure) of these resins assure the quality of the final peptide.