In contrast to the safety and high efficacy of radiofrequency (RF) catheter ablation in curing most forms of SVT, limited data are available to assess the role of RF ablation in ventricular tachycardia (VT). RF ablation is reported to have a success rate up to 90% in most series of idiopathic VT especially Right ventricular outflow tract (RVOT) tachycardia. We are hereby reporting our experience in RF catheter ablation of 25 cases of idiopathic VT (18 M and 7 F), mean age (38.7 + 11 ys), having structurally normal hearts. ECG during the tachycardia showed RBBB in 9 pts, LBBB in 16, Rt axis deviation in 6, left axis deviation in 10 and normal axis in 9 pts. All cases underwent complete EP study including: a) Tachycardia Induction by means of programmed electrical stimulation (PES), and incremental ventricular pacing, facilitated by iv Isuprenaline infusion at incremental rates of 0.3-0.8 g/Kg/min in some cases of nonsustained VT. B) tachycardia localization using Pacemapping with at least 11 out of 12 leads identical to the surface ECG during tachycardia and Activation mapping with the RF activation signals at least 20 msec earlier than QRS on the surface ECG. C) RF Catheter Ablation was attempted in all cases at the chosen site by pacemapping, and activation mapping. Pressure mapping was successful in identifying the proper site in one pt with Left VT. An average of 10 attempts of RF energy applications was needed in each case with a mean total fluroscopic time of 109 minutes.Results: Tachycardia sites were found to be in the septal side of RVOT in 8 pts, free wall in 7 pts and one case in the inflow tract of RV. In LVT 4 were found in the inferoposterior part and 5 in the infero ant. Part of septum. Successful RF catheter ablation of idiopathic VT was achieved in 20 out of the 25 pts (80%) as proved by termination of the tachycardia in 16 pts, failure of tachycardia induction by both PES and Isuprel in 20 pts or the induction of non specific multiform VT in 2 pts. No complications were reported in all 25 pts. All the 20 cases were discharged on no antiarrhythmic drugs with no reported tachycardia on follow up for a minimum of 3 months upto 3 ys. Two pts had recurrence and were subjected to successful redo ablation.Conclusions: The techniques of pacemapping and activation mapping have been successfully used in localizing the site of origin of VT and hence the efficacy of RF catheter ablation. RF catheter ablation is a safe, technically feasible and highly successful means of curing idiopathic VT particularly RVOT tachycardia. This modality of therapy should be tried in every pt with structurally normal heart as it abolishes the need for long term antiarrhythmic therapy with its doubtful efficacy and possible hazards.