Objective The goal of this study was to examine the association between urotensin Ⅱ (U Ⅱ) concentration and the severity of coronary artery disease (CAD). Methods We studied U Ⅱ concentrations in 100 patients with known or suspected CAD referred for cardiac catheterization. Based on coronary angiograms, subjects were classified as having no or mild CAD (stenosis <50%) and significant CAD (stenosis=50%). Micheal score system was used to estimate the severity of CAD. Result U Ⅱ concentration in the significant CAD group had no difference compared with the no or mild CAD group (1.95±1.18pmol/L vs 2.04±1.47pmol/L, P>0.05), but higher in the severe group (score =9) than in the normal or nearly normal group (score<3)(2.50±1.62pmol/L vs 1.61±1.05pmol/L, P=0.03). UⅡ concentration had no relationship with other known risk factors, but it correlated with CAD severity (r=0.213, P=0.034). In multiple regression analysis, U Ⅱ is one of the determinants of the severity of CAD, other than age, abnormal glucose, hypertension and gender. Conclusios U Ⅱ is elevated in severe CAD and there is a significant relationship between U Ⅱ concentration and CAD severity. (J Geriatr Cardiol 2007;4:229-232.) Objective The goal of this study was to examine the association between urotensin Ⅱ (U Ⅱ) concentration and the severity of coronary artery disease (CAD). Methods We studied U Ⅱ concentrations in 100 patients with known or suspected CAD referred to cardiac catheterization. on coronary angiograms, subjects were classified as having no or mild CAD (stenosis <50%) and significant CAD (stenosis = 50%). Micheal score system was used to estimate the severity of CAD. had no difference compared with the no or mild CAD group (1.95 ± 1.18 pmol / L vs. 2.04 ± 1.47 pmol / L, P> 0.05), but higher in the severe group (score = 9) than in the normal or nearly normal group (score <3) (2.50 ± 1.62 pmol / L vs. 1.61 ± 1.05 pmol / L, P = 0.03) .UII concentration had no relationship with other known risk factors, but it correlated with CAD severity (r = 0.213, In multiple regression analysis, UII is one of the determinants of the severity of CAD, other than age, abnormal glucose, hypertension and gender. Conclusios U II is elevated in severe CAD and there is a significant relationship between U Ⅱ concentration and CAD severity. (J Geriatr Cardiol 2007; 4: 229-232.)