Humanmilk pepsin and pancreatin digests were separated using molecular membrane and reverse phase chromatography. Chemical screening of the resulting fractions using the ORAC antioxidant assay yielded a peptide fraction (PF-23) with high antioxidant activity (5207 μM Trolox Equivalents (TE)/g). Tandem mass spectrometry allowed the identification of twenty peptides. Eight small molecular weight peptides from 4 to 6 amino acids were synthesised and screened for antioxidant properties using ORAC and linoleic acid emulsion. On ORAC, the peptides YGYTGA (5169 μM TE/mmol) and ISELGW (4479 μM TE/mmol) were the most active. At 250 μM peptide ISELGW and its derivatives significantly reduced hydroperoxides formed during autoxidation of linoleic acid for 4 days at 50 °C. Further testing of these peptides may allow their inclusion in infant formulas to reduce the incidence of oxidative stress-mediated diseases in newborns.