Proteins and peptides that are made entirely of D-amino acids are resistant to proteolytic metabolism, resulting in longer half-lives and markedly reduced immunogenicity. These inherent properties make D-proteins and D-peptides near ideal molecules for pharmaceutical products. Several drugs contain D-amino acids with Parsabiv (etelcalcetide), a 7 D-amino acid peptide disulfide linked to L-cysteine, having the greatest D-amino acid content so far among marketed products. The technology of mirror image phage display combined with advances in chemical protein synthesis have enabled the systematic discovery and development of D-proteins with potencies that rival the activities of antibodies. This talk will highlight the technology behind this emerging field with examples of D-products currently in the pipeline.