Objective Analyzing risk factors for gastrointestinal bleeding(GIB) after coronary artery bypass grafting(CABG). Methods 582 cases undergoing CABG from August 2001 to May 2005 were divided into two groups (GIB group ,n=6 ;control group,n=576) . Preoperative , operative and postoperative clinic data were com-pared. Results The ratio of over-aging(age greater than 70), hypertension, cerebrovascular disease, myocardial in-fraction,heart function (NYHA) over Ⅲ and postoperative low output syndrome (LOS) in GIB group were signifi-cantly higher than that in control group;age, blood transfusion and hospitalized time were significantly higher and left ventricular ejective fraction was significantly lower in GIB group than that in control group. Age over 70,history of myocardial infraction and heart function (NYHA) over Ⅲ were selected as risk factors of GIB after CABG by step-wise logistic regression analysis. Conclusions It is very useful for precaution, early diagnosis and early therapy of GIB after CABG to evaluate if patients have the risk factors of GIB after CABG before operations.