Omega-3 (omega-3) polyunsaturated fatty acids (PUFAs) from fish and fish oils appear to protect against coronary heart disease: their dietary intake is in fact inversely associated with cardiovascular disease morbidity/mortality in population studies. Recent evidence suggests that at least a part of this protective effect is mediated by a relatively small but significant decrease in blood pressure (BP) level. In fact, omega-3 PUFAs exhibit wide-ranging biological actions that include regulating both vasomotor tone and renal sodium excretion, partly competing with omega-6 PUFAs for common metabolic enzymes and thereby decreasing the production of vasoconstrictor rather than vasodilator and anti-inflammatory eicosanoids. PUFAs also reduce angiotensin-converting enzyme (ACE) activity, angiotensin II formation, Tumor Growth Factor-beta (TGF-beta) expression, enhance endothelial nitric oxide (NO) generation and activate the parasympathetic nervous system. The final results are improved vasodilation and arterial compliance of both small and large arteries. Preliminary clinical trials involving normotensive and hypertensive dyslipidaemic patients, diabetics and elderly subjects, confirm this working hypothesis: 3 meta-analyses suggest that PUFAs are able to slightly, but significantly improve arterial hypertension. Future research will clarify if PUFA supplementation could improve the antihypertensive action of specific BP lowering drug classes and of statins.