Atrial flutter may now be very frequently and definitely cured in a single session of radiofrequency ablation. However, the very name of atrial flutter gives rise to a certain confusion. Clinical experience from everyday activity in ablation laboratories, especially since the introduction of new mapping techniques, has shown that this entity is in fact multiple. Flutters may be classified by their electrocardiographic appearance and/or their electrophysiological mechanism with as many prognostic as therapeutic implications. This article reviews diagnostic features of typical and atypical flutter and the different treatments which may be proposed in different clinical situations.