Typical atrial flutter is a common atrial tachyarrhythmia. Symptoms are typically related to the rate of ventricular response. Although atrial flutter with 1:1 atrioventricular conduction is rare, it is important to recognize because it may precipitate rapid hemodynamic compromise. The authors present a case of exercise-induced 1:1 atrioventricular conduction in a patient with typical atrial flutter.