Background and Objective Overt gastrointestinal bleeding (GIB) is one of the noncardiac complications in patients with acute myocardial infarction (AMI). Identification of patients at increased risk of overt GIB could aid in targeting more aggressive treatment, and lead to improved outcomes. The aim of this study is to determine the frequency, risk factors, and prognostic significance of overt GIB in patients with AMI. Methods A retrospective review of the medical records of 1443 patients admitted to the Chinese PLA General Hospital with AMI was conducted. Charts were reviewed for clinical characteristics, possible precipitating factors and complications. Patients were categorized as having or not having overt GIB(GIB associated with hemodynamic changes or the need for transfusions). Results Twenty nine (2.0%) patients developed overt GIB within 30 days after AMI. Patients with overt GIB had higher 30-day mortality rate than those without (44.8% vs. 9.9%, P < 0.001). Multivariate logistic regression analysis showed major determinants of in-hospital overt GIB secondary to AMI were gender of female (odds ratio 2.41, 95% confidence interval [CI] 1.08 to 5.37), age=75 years (odds ratio 1.58, 95% CI 1.13 to 2.20), prior history of AMI (odds ratio 2.28, 95% CI 1.17 to 4.88), pneumonia (odds ratio 3.47, 95% CI 1.50 to 8.03) and anemia at admission (odds ratio 2.37, 95% CI 1.04 to 5.37). Conclusions In patients with AMI, overt GIB is associated with higher in-hospital mortality, and female sex, older age, prior AMI, pneumonia and anemia at admission are predictors of overt GIB during hospitalization.