The paroxysmal supraventricular tachycardias (SVT) are commonly encountered arrhythmias and include atrioventricular nodal re-entrant tachycardia, atrioventricular reciprocating tachycardia, and focal atrial tachycardia. These tachycardias share several clinical features as well as similar management strategies. The probable mechanism of paroxysmal SVT can often be diagnosed from the clinical findings and a 12-lead ECG. This review describes the initial evaluation and treatment of patients with paroxysmal SVT, including distinctive features from the most important differential diagnoses.