Aim To investigate the plasma C-type natriurtic peptide (CNP) and atrial natriuretic peptide (ANP) levels of patients with coronary atherosclerosisor coronary heart disease before and after angioplasty in order to study the relationship between C-type natriurtic peptide and coronary atherosclerosis and angioplasty. Methods Seventeen patients with coronary atherosclerosis (coronary stenosis less than 20%) and ten patients with coronary heart disease (coronary stenosis more than 80%～100%) before and after left coronary PTCA and/or stenting were selected. Blood samples were extracted from coronary sinus, femoral artery and vein respectively as well as from elbow vein at 24 h, 72 h after angioplasty. Blood samples were also extracted from elbow vein of seventeen healthy controls. The plasma CNP and ANP levels were measured using radioimmunoassay. Results Venous plasma CNP levels of patients with coronary atherosclerosis and coronary heart disease were higher than those of controls(P<0.001). The plasma ANP level in coronary sinus increased significantly after angioplasty (P<0.05). Plasma CNP levels in coronary sinus, femoral artery, and femoral vein immediately after angioplasty were all obviously elevated (P<0.001). Venous plasma CNP level after 24 h was the highest. After 72 h, the plasma CNP level returned to that before angioplasty. Conclusions CNP is involved in the pathophysiologic process of coronary atherosclerosis and intervention of coronary heart disease. The changes of plasma CNP and ANP levels after angioplasty in coronary heart disease suggest that CNP can reflect the changes of coronary artery better than ANP.