Aims The left atrial appendage (LAA) is one of the major sources of atrial tachycardias (ATs) in children. However, endocardial ablation in LAA may fail or even cause fatal tamponade; and epicardial ablation with subsequent surgical appendectomy (SAE) may be required. There is no relevant report in children. We aimed to evaluate the feasibility of epicardial ablation with SAE in children. Methods and results The epicardial ablation with SAE was performed in a 12-year-old girl with an incessant AT. Endocardial mapping demonstrated endocardial activation time of −112 msec and −105 msec (relative to the onset of the A wave at CS9-10) in the right ventricular outflow tract and LAA, respectively. But multiple ablation attempts at these sites did not terminate the AT. After the left-side pericardium opened, the earliest activation (−120 msec) during AT was found at the apex of upper lobe. At this site, ablation eliminated the tachycardia within 5 seconds of onset of energy. After ablation, the LAA was excited, followed by a continuous over and over suture to definitely close the resection line. The free of AT and a decrease in LAD and NT-proBNP were achieved during the 12-month follow-up. Conclusion The epicardial ablation with subsequent SAE was successfully performed in a child. The heart function of the patient improved after a 12-month follow-up. The excision of LAA may be an ideal strategy for children with incessant AT originating from epicardial LAA. However, the long-term safety and efficacy of SAE in children should be further estimated.