Aldosterone synthase is a mitochondrial enzyme that catalyzes the conversion of 11-deoxycorticosterone to the potent mineralocorticoid aldosterone. The gene encoding aldosterone synthase, CYP11B2, is associated with essential hypertension. But if the genetic variations in aldosterone synthesis could influence the antihypertensive response to Valsartan is not clear. A Chinese sample of 502 persons (217 women) was studied, which was divided into the hypertensive group (EH) of 345 persons and the normotensive group (NB) of 157 persons. Subjects were genotyped through the use of the polymerase chain reaction for the diallelic polymorphisms in CYP11B2. 98 persons of the essential hypertension group received 4 weeks therapy with valsartan. Blood pressure, 24-hour ambulatory blood pressure, biochemical index were also determined. The frequency of CC+CT genotypes in hypertensive group was significantly higher than that in normotensive group (P<0.05), the frequency of C allele of gene CYP11B2 (-344T/C) in hypertensive group was significantly higher than that in normotensive group (P<0.01). The descending values of SBP (systolic blood pressure), DBP (diastolic blood pressure), MAP (mean arterial pressure), 24 h SBP (mean SBP of 24 hours), 24 h DBP (mean DBP of 24 hours), 24 h MAP (mean arterial pressure of 24 hours) of CC+CT genotype group were significantly higher than those of the TT genotype group (P<0.05). The aldosterone synthase CYP11B2 (-344T/C) gene polymorphism is associated with essential hypertension in Chinese. And the aldosterone synthase CYP11B2 (-344T/C) gene polymorphism may be the predictor of the antihypertensive response to Valsartan.