Ectopic atrial tachycardia (EAT) is an uncommon type of supraventricular tachycardia. It is usually chronic, incessant and resistant to pharmacologic therapy. Radiofrequency catheter ablation, which has become one of the treatments of choice for the more common types of supraventricular tachycardia, has recently also been shown to be effective in EAT. Radiofrequency catheter ablation was attempted in three patients with incessant EAT. Two of the patients, aged 7 and 13 years, had signs of left ventricular dysfunction, and the EAT originated in the left atrium. The remaining patient, aged 72 years, had a right EAT with normal left ventricular function. Radiofrequency ablation was guided by endocardial atrial mapping to locate the site of earliest atrial activation. Ablation was successful in all three patients, with complete cure of the tachycardia for a follow-up period of 12 to 19 months. Radiofrequency catheter ablation of EAT is highly successful and should be considered as one of the treatments of choice for this arrhythmia.