A 70-year-old patient with acute renal infarction due to chronic atrial fibrillation is presented. The clinical presentation of the patient was suggestive of renal colic. Computerized tomography was consistent with acute renal infarction and confirmed the diagnosis. After giving anticoagulation and antiarrhythmic treatment, she was discharged with clinical improvement. High clinical suspicion is necessary on an old patient who has thromboembolic risk factors with the complaint of abrupt-onset flank pain.