We have evaluated the changes in arterial blood pressure caused in spontaneously hypertensive rats (SHR) by long-term intake of an Enterococcus faecalis CECT 5728-fermented milk with significant angiotensin-converting enzyme (ACE)-inhibitory activity. After being weaned, male 3-week-old SHR were randomized into five groups. Until the 20th week of life, rats in each group were given one of the following drinking fluids: tap water (negative control 1), a fermented milk without ACE-inhibitory activity (negative control 2), captopril (100 mg/kg) (positive control), the E. faecalis CECT 5728-fermented milk that had significant ACE-inhibitory activity, or Ca-enriched E. faecalis CECT 5728-fermented milk. Animals in the different groups were then given tap water as drinking fluid from the 20th to 25th week of life. Systolic blood pressure (SBP) and diastolic blood pressure (DBP) were measured weekly in the rats, from the 6th to 25th week of life, by the tail-cuff method. A definite decrease in SBP and DBP could be observed in the rats treated with captopril and also in the rats that received the E. faecalis CECT 5728-fermented milks. The greatest antihypertensive effect was observed when the pharmacological treatment was administered. The effect of the Ca-enriched fermented milk was slightly more accentuated and more constant than the effect of the E. faecalis CECT 5728-fermented milk that had not been enriched in Ca. SBP and DBP increased in the treated SHR when the corresponding antihypertensive treatment was removed. Fermentation of milk with E. faecalis CECT 5728 may therefore be a successful strategy to produce a functional food with antihypertensive activity.