Cardiac arrhythmias refer to any abnormality or disturbance in the normal activation sequence of the myocardium and may be indicative of structural heart disease and the cause of significant cardiovascular complications and sudden cardiac death. The following review summarizes the current state-of-the-art knowledge on the role of echocardiography in the management of cardiac arrhythmias and focuses on atrial fibrillation and ventricular arrhythmias where echocardiography presents a particular diagnostic and prognostic interest. Moreover, a brief reference is made to the effect of cardiac arrhythmias and conduction abnormalities on echocardiographic examination.