Recent studies have shown that antihypertensive drugs like diuretics increase plasma homocysteine (Hcy) levels. However, the effect of other antihypertensive drugs on plasma Hcy levels has not been tested extensively. The aim of present study was to investigate the effect of antihypertensive therapy (AHT) on Hcy levels in essential hypertensive subjects. A case-control study of 273 patients with essential hypertension (EH) and 103 normotensive controls was undertaken. Plasma Hcy levels were measured before and after 6 weeks of AHT. The genotyping of MTHFR C677T polymorphism was performed by polymerase chain reaction-restriction fragment length polymorphism. Angiotensin-converting enzyme (ACE) inhibitors and beta-blockers significantly decreased and hydrochlorothiazides significantly increased the plasma Hcy levels in hypertensive patients (P<0.05). No significant association between MTHFR C677T genotypes and changes in Hcy levels in response to antihypertensive was observed in EH patients. The decrease in Hcy induced by beta-blockers and ACE inhibitors observed in our study may be due to the improvement of endothelial function along with improved renal function. Thus, our results suggest that ACE inhibitors and beta-blockers may provide additional beneficial therapeutic effects to the EH patients by decreasing Hcy levels.