Abstract: Objective To assess the relationship between serum omentin-1levels and arterial elasticity among essential hypertensive patients with obesity. Methods A total of 255 subjects with normal blood pressure or essential hypertension were recruited,and they were divided into 4groups:the normal control（NC）（n=65）,hypertension（H）（n=66）,obesity（O）（n=63）,and the hypertension with obesity（HAO）groups（n=61）according to blood pressure and body mass index（BMI）. Serum omentin-1 was measured by enzyme-linked immunosorbent assay（ELISA）method and brachial-ankle pulse wave velocity（baPWV）by Colin Arteriosclerosis Instrument for all study subjects. Results Serum omentin-1levels were significantly higher in the NC group（233.7±57.5）μg/Lthan in the H group（176.7±53.4）μg/L,the O group（151.4±48.2）μg/Land the HAO group（143.3±47.2）μg/L,respectively（all P＜0.01）. Serum omentin-1levels were lower in the HAO group than in the H group（P＜0.01）and exhibited a decreasing trend relative to the O group without statistically significant differences（P＞0.05）.Of four groups examined,brachial-ankle pulse wave velocity（baPWV）was highest in the HAO group （1413.8±67.7）cm/s,all P＜0.05and it was higher in the H （1354.8±91.6）cm/sand O （1366.1±81.7）cm/sgroups than in the NC group（1206.2±168.0）cm/s（both P＜0.01）. Obesity was observed to affect serum omentin-1levels irrespective of the presence of hypertension,while hypertension played a contributing role only in non-obese subjects. Pearson correlation analyses showed that serum omentin-1was negatively related with BMI,systolic blood pressure（SBP）,pulse pressure,triglyceride,total cholesterol,low density lipoprotein cholesterol（LDL-C）,and baPWV,while positively related with high density lipoprotein cholesterol（HDL-C）（all P＜0.05）. Factorial analyses indicated an interaction between hypertension and obesity on serum omentin-1levels. In multivariate linear regression analyses,BMI,SBP,LDL-C and HDL-C were significantly associated with baPWV（all P ＜0.05）.Conclusion Serum omentin-1may exert a negative effect on arterial elasticity hypofunction,as well as arterial elasticity. Moreover,the effect of obesity on serum omentin-1was more obvious than that of hypertension.