Background. According to the recent data in up to 10% of the patients with ventricular tachycardia (VT) there is an absence of structural heart disease. Several types of VT could be present in such patients: right ventricular outflow tract (RVO T) VT, caticholaminergic polymorphic VT, idiopathic left VT, Brugada syndrome, long QT syndrome. According to the VT type the management can be pharmacological therapy, radio-frequency ablation, implantation of cardioverter defibrillator or a combination of them. The decision about the management is based on the type of VT, data obtained from echocardiography, magnetic resonance imaging (MRI) and electrophysiological study (EPS). Case report. We present a case of a 48 years old female who had frequent attacks of palpitations with presyncopes. On Holter ECG monitoring there were 32066 premature ventricular complexes (PVCs) and 493 non-sustaned episodes of VT during 24 hours with left bundle branch block morphology, inferior axis and transition zone in V4. The patient could not receive amiodarone because of an allergic reaction. Treatment with beta-blockers, verapamil and propafenone was tried but with no sufficient improvement. On echocardiography and MRI she had no structural heart disease. We suspected RVOT VT and evaluated the patient during EPS, where RVOT VT was induced. The earliest activation point was find to be in postero-septal RVOT area and several applications of radio-frequency energy were performed. Immediately after ablation there were no more PVCs, with solitary PVCs in next days. She continued the medical treatment with bisoprolol 5mg/day and propafenone 300 mg/day. We evaluated the patient after one month on Holter ECG. There was a decrease of PVCs number to 4123, but were 137 non-sustained paroxysms of VT during 24 hours. We decided to repeat the ablation. On basal ECG during second EPS there were no PVCs, but they appeared after dobutamine infusion. Radio-frequency energy was applied in postero-septal RVOT area with disappearance of PVCs. The patient continued the treatment with metoprolol 100mg/day. On Holter ECG monitoring after one month there were 5195 PVCs during 48 hours and no more paroxysms of VT. We recommended to continue the treatment with metoprolol 100md/day only. Conclusions. Electrophysiological study is an important tool in evaluating ventricular tachycardia and radio-frequency ablation is a therapy of choice is selected patients.