Aim To investigate the association between plasma omentin-1 level and left ventricular hypertrophy （LVH） in patients with essential hypertension （EH）. Methods We randomly enrolled 55 essential hypertensive patients with or without left ventricular hypertrophy （LVH）,and 32 participants with normal blood pressure.We measured plasma omentin-1 and nitric oxide （NO） levels.Left ventricular hypertrophy was assessed by left ventricular mass index （LVMI）. Results Plasma omentin-1 and nitric oxide levels were significantly decreased in essential hypertensive patients compared to normal control group （P<0.05）,and were further reduced in essential hypertensive patients with left ventricular hypertrophy compared to those without left ventricular hypertrophy （P<0.05）.Pearson correlation analysis showed that plasma omentin-1 was significantly positively related with NO （r＝0.565,P<0.01）,and significantly negatively related with systolic blood pressure,diastolic blood pressure,mean arterial blood pressure,pulse pressure,LVMI （r＝－0.713,－0.699,－0.788,－0.311,－0.675,P<0.05 or P<0.01）.Multiple linear regression analysis showed that omentin-1 was independently related with systolic blood pressure and diastolic blood pressure in patients with EH （bomentin-1＝－2.140,P<0.05 bomentin-1＝－1.382,P<0.05）.Omentin-1 and hypertension course were independently related with LVMI in patients with EH （bomentin-1＝－5.980,P<0.05 bhypertension course＝0.103,P<0.05）. Conclusions Plasma omentin-1 level decreases in hypertensive patients.Omentin-1 is positively related with nitric oxide,and is negatively related with LVMI in essential hypertensive patients.Omentin-1 may be an independent indicator for LVH in essential hypertensive patients.