Objective:To investigate the relationship between aldosterone escape phenomena and left ventricular hypertrophy(LVH)in essential hypertension(EH) treated by angiotensin-converting enzyme inhibitor(ACEI) and angiotensinⅡ receptor inhibitor blocker(ARB). Methods:Totally 95 cases of EH complicated with LVH were randomly divided into enalapril group(n=48) and irbesartan group(n=47). AngiotensinⅡ(AngⅡ),aldosterone(Ald),interventricular septal thickness(IVST),left ventricular posterior wall thick-ness(PWT)and left ventricular end diastolic diameter(LVDD) levels were examined before therapy and at 1,3,6 months after thera-py. Results:(1)Levels of blood pressure were decreased in both groups and there was no significant difference between two groups(P >0.05). (2)In enalapril group,AngⅡlevels were all decreased significantly(P <0.05) at 1,3,6 months after therapy. AngⅡlevels were slightly increased at 3,6 months after therapy compared with those at 1 month after therapy,but without statistical differences(P >0.05). Ald levels were decreased significantly at 1 month after therapy compared with those before therapy(P <0.05) but they were increased at 3,6 months after therapy,reaching the levels before therapy(P >0.05). In irbesartan group,AngⅡlevels were increased at 1 month after therapy compared with those before therapy,without statistical differences but they were increased at 3,6 months af-ter therapy compared with those before therapy,with statistical differences(P <0.05). Levels of Ald were all decreased significantly at 1,3,6 months after therapy compared with those before therapy(P <0.05). (3)IVST,PWT,LVDD levels were decreased in both groups after therapy compared with those before therapy(P <0.05) but there was no significance between two groups. Ald levels of some patients(19 patients in enalapril group and 2 patients in irbesar-tan group) were initially decreased but were increased after 3 months’ therapy compared with those before therapy,which was called Ald escape. LVH ameliorations of these paitents were quiet. Conclusions:Ald escape may occur in EH treated by ACEI and ARB. LVH ameliorations in these paitents with Ald escape phenomena are quiet.