Background: Fasciculoventricular (FV) pathways are considered a rare form of ventricular preexcitation which do not give rise to reciprocating tachycardias. Few FV pathways have been reported, and none have been coexisted with atrioventricular nodal reentrant tachycardia(AVNRT). ECG findings of FV pathways may be misinterpreted as Wolff-Parkinson-White syndrome with anteroseptal accessory pathways. Especially if FV pathways were coexisted with fast/slow form of AVNRT, there is a chance to damage to the AV node or the His bundle system if such pathway is mistakenly targeted for catheter ablation. Methods and Results: From January 1993 to July 2004, total six (3.0%) of 194 patients underwent electrophysiologic studies for evaluation of preexcitation on surface ECG were diagnosed as FV pathways. FV pathways were diagnosed when the electrophysiologic findings met all of the following criteria: 1) normal AH interval, 2) short and fixed HV interval, 3) atrial pacing produces AH prolongation due to AV nodal delay without change of preexcitation degree, and 4) His bundle stimulation produces preexcited QRS with short HV interval. Two of six patients were coexisted with AVNRT. One patient had AVNRT of slow/fast form and the others had AVNRT of fast/slow form. None of FV pathways have been implicated in any reentrant arrhythmia. Conclusion: FV pathways were in charge of a fixed ventricular preexcitation and served as a bystander during AVNRT. In patients of FV pathways with palpitation, electrophysiologists need to find out other causes of tachycardias.