Folic acid (FA) is a member of the B-vitamin family with cardiovascular roles in homocysteine regulation and endothelial nitric oxide (eNOS) activity. Its interaction with eNOS is thought due to enhancement of tetrahydrobiopterin (BH4) bioavailability and also possibly to a direct enzyme interaction, both helping maintain eNOS in its coupled state to favour the generation of nitric oxide (NO) rather than oxygen free radicals. FA also plays a role in the prevention of several cardiac and non-cardiac malformations, has potent direct antioxidant and anti-thrombotic effects, and can interfere with the production of the endothelial-derived hyperpolarizing factor. These multiple mechanisms of action have led to studies regarding the therapeutic potential of folic acid for cardiovascular disease. To date, studies have shown FA ameliorates endothelial dysfunction and nitrate tolerance, and can improve pathologic features of atherosclerosis. These effects appear to be homocysteine-independent but rather related to its role on eNOS function. Given growing evidence that NOS uncoupling plays a major role in many cardiovascular disorders, the potential for exogenous FA as an inexpensive and safe oral therapy is intriguing and is stimulating ongoing investigations.