Radiofrequency catheter modification of the sinus node for persistent inappropriate sinus tachycardia has not been previously reported. This article describes a patient in whom radiofrequency current was used to ablate an incessant automatic tachycardia focus mapped to the region of the sinus node, where a discrete multicomponent electrogram demonstrating earliest atrial activation was recorded. A transient junctional rhythm developed immediately after ablation, with rapid subsequent emergence of a stable rhythm having normal sinus nodal characteristics.