Catheter ablation of ectopic atrial tachycardia has been previously reported in a small number of patients in whom the ectopic focus was predominantly located in the right atrium. We report on a 51‐year‐old patient with atrial automatic tachycardia originating in the left atrium, in whom successful radiofrequency catheter ablation was pet formed via a transseptal puncture. The patient had suffered incessant atrial tachycardia for several years, refractory to antiarrhythmic drug treatment and DC‐cardioversion. Radiofrequency ablation terminated left ectopic atrial tachycardia and, therefore, should have been attempted before resorting to open heart surgical abl