Heart failure is one of the leading death reasons in the world. Left atrial appendage (LAA) is of great importance in maintaining cardiac function. We examined the effect of carvedilol therapy on left atrial appendage functions in patients with symptomatic congestive heart failure. Twenty patients with symptomatic congestive heart failure and resting ejection fraction <= 40% were included in this study. LAA was visualized by transesophageal echocardiography. LAA area change (LAAAC), LAA empty velocity (LAAEV) and LAA empty velocity time integral (LAAEVTI) were calculated as the average of five cardiac cycles. A minimum dose of carvedilol administered to each patient, was titrated up to maximal dose that the patients could tolerate, during an 8-week period. After the third month of completing treatment, a second transthoracic and transesophageal echocardiographic study was performed. Heart rate (P < 0.001), systolic (P = 0.002) blood pressures were reduced by carvedilol therapy at the end of the third month. LAAEV (P < 0.001), LAAEVTI (P < 0.001), and LAAAC (P < 0.001) were significantly increased at the end of the third month of carvedilol therapy. This study indicates that in patients with symptomatic congestive heart failure, carvedilol therapy is associated with an improvement in left atrial appendage function.