Background: Smoking is associated with endothelial dysfunction and arterial stiffness. Supplementation of omega-3 PUFAs is associated with better prognosis. Aim of this study was to evaluate the effects of omega-3 polyunsaturated fatty acids (PUFAs) supplementation on smoking-induced impairment of arterial function. Methods: We studied the effect of a 12 weeks oral treatment with 2gr/day of omega-3 PUFAs in 20 healthy smokers on three occasions (day0: baseline, day28 and day84). The study was carried out on two separate arms (omega-3 fatty acids and placebo), according to a randomized, placebo-controlled, double-blind, cross-over design. Measurements were carried out before (pSm), immediately and 20 min after cigarette smoking. Endothelial function was evaluated by flow-mediated dilation (FMD) of the brachial artery. Carotid-femoral pulse wave velocity (PWV) was measured as an index of aortic stiffness and augmentation index (AIx) as a measure of arterial wave reflections. Circulating levels of tumor necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6) and plasminogen activator inhibitor-1 (PAI-1) were measured. Results: Compared with placebo, omega-3 PUFAs treatment resulted in a significant improvement in pSm values of FMD (p < 0.05), AIx (p < 0.001) and PWV (p < 0.01). Although, acute cigarette smoking decreased FMD and caused an increase in AIx and PWV, omega-3 PUFAs treatment blunted the acute smoking-induced impairment of FMD (p < 0.001), AIx (p < 0.05) and PWV (p < 0.05) and significantly decreased levels of TNF alpha (p < 0.05) and IL-6 (p = 0.01) and increased levels of PAI-1 (p = 0.05). Conclusions: Omega-3 PUFAs improved endothelial function and the elastic properties of the arterial tree in healthy smokers, with a parallel anti-inflammatory effect. (c) 2011 Elsevier Ireland Ltd. All rights reserved.