Objectives: We tested the hypothesis that perception of control moderates any relationship between anxiety and in-hospital complications (i.e., recurrent ischemia, reinfarction, sustained ventricular tachycardia or fibrillation, and cardiac death) in patients with acute myocardial infarction (AMI). Background: Anxiety is common among patients with AMI, but whether it is associated with poorer outcomes is controversial. Conflicting findings about the relationship of anxiety with cardiac morbidity and mortality may result from failure to consider the moderating effect of perceived control. Methods: This was a prospective examination of the association among anxiety, perceived control, and subsequent in-hospital complications among patients (N = 536) hospitalized for AMI. Results: Patients’ mean anxiety level was double that of the published mean norm. Patients with higher levels of perceived control had substantially lower anxiety (p = .001). A total of 145 (27%) patients experienced one or more in-hospital complications. Patients with higher levels of anxiety had significantly more episodes of ventricular tachycardia, ventricular fibrillation, and reinfarction and ischemia (p < .01 for all). In a multivariate hierarchical logistic regression model, left ventricular ejection fraction, history of myocardial infarction, anxiety score, and the interaction of anxiety and perceived control were significant predictors of complications. Conclusion: Anxiety during the in-hospital phase of AMI is associated with increased risk for in-hospital arrhythmic and ischemic complications that is independent of traditional sociodemographic and clinical risk factors. This relationship is moderated by level of perceived control such that the combination of high anxiety and low perceived control is associated with the highest risk of complications. AMI = acute myocardial infarction; CHD = coronary heart disease; BSI = Brief Symptom Inventory; CAS = Control Attitudes Scale.