OBJECTIVE To investigate the frequency and basis of clinically relevant computed tomographic (CT) findings in patients with atrial fibrillation and acute abdominal pain. MATERIALS AND METHODS We retrospectively identified 30 patients with atrial fibrillation referred for enhanced (n = 26) or unenhanced (n = 4) abdominal CT from our emergency department because of acute nontraumatic abdominal pain. All CT images were independently reviewed by a single reader who evaluated the studies for findings that might explain acute pain. Results were correlated with laboratory and surgical findings, clinical course and outcome, and final diagnosis. RESULTS Eleven (37%) of the 30 patients had CT findings for abdominal pain that related to atrial fibrillation, including end-organ ischemia or infarction (n = 8, 27%) and spontaneous hemorrhage presumably related to anticoagulation (n = 3, 10%). Of the remaining patients, 5 (17%) had nonatrial fibrillation-related CT findings for abdominal pain, and 14 (47%) had no cause for abdominal pain found at CT. CONCLUSIONS Patients with atrial fibrillation who present to CT with acute abdominal pain have a high likelihood of being found with abdominal pathology relating to their atrial fibrillation, such as arterial embolus or hemorrhage, and a lower likelihood of having more typical causes for abdominal pain. Increased awareness of the high likelihood of atrial fibrillation-related causes for abdominal pain may improve diagnoses and triage for this special and difficult population.