Abstract Background: Radiofrequency catheter ablation (RFCA) is an effective method to cure both supraventricular and ventricular arrhythmia (VA) in certain centres. Aim: To assess the results of RFCA in VA at Siriraj Hospital. Method: Electrophysiologic study, mapping, using both earliest endocardial activation and pace mapping, and ablation were performed. Results: Thirty patients with symptomatic VA underwent RFCA. The mean age was 44 years. Eight patients had underlying heart disease (two prolapsed mitral valve, three myocarditis, two dilated cardiomyopathy and one mitral stenosis). Thirty‐six morphologies of VA were detected from the study. Thirty‐three morphologic tachycardias attempted were successfully ablated; 17, 10 and six were right VT, left VT and premature ventricular contraction (PVC), respectively. Failure of ablation occurred in one patient with left VT. Only minor complications occurred in this study.There was no difference in cycle length and endocardial activation time between right and left VT. 12/12 identical pace mapping was more easily performed in right VT than in left VT The fluoroscopic and procedure times in left VT were significantly longer than in right VT.Relapse occurred in six patients. Re‐ablation was successfully performed in four patients, giving a final success rate of 93%.