The potential of bovine lactoferrin (LF) as a source of antihypertensive peptides has been examined. For this purpose, LF pepsin hydrolysate with molecular mass lower than 3kDa (LFH<3kDa) was prepared and orally administered to spontaneously hypertensive rats (SHR), resulting in reduced systolic blood pressure in a significant and maintained manner up to 24h after administration. LFH<3kDa was further fractionated by semi-preparative high performance liquid chromatography (HPLC) and 38 peptides, contained in the active fractions, were identified by using an ion trap mass spectrometer. Based on the peptide abundance, a total of 11 peptides were chemically synthesized and their ACE inhibitory activity tested. Only three of them, corresponding to peptides of sequences LIWKL, RPYL and LNNSRAP exerted in vitro inhibitory effects on angiotensin I converting enzyme (ACE) activity and had a 50% inhibitory concentration (IC₅₀) of 0.47, 56.5 and 105.3μM, respectively. The three peptides also showed antihypertensive effects in SHR and remarkably the effect of LIWKL remained significant for up to 24h post-administration, similarly LFH<3kDa and the captopril control. The two most potent in vitro inhibitory peptides showed ex vivo inhibitory effect on ACE-dependent vasoconstriction as well. In conclusion, three novel LF-derived peptides and a pepsin LFH<3kDa lowered blood pressure and exhibit potential as orally effective antihypertensive compounds.