Introduction: Most focal atrial fibrillation (AF) can be triggered by premature beats from pulmonary veins (PVs), and ablation of these foci could cure AF. However, it is difficult to locate the trigger points of PVs using only one mapping catheter. The purpose of the present study was to investigate the efficacy of using four mapping catheters in four PVs simultaneously in the ablation of focal AF. Methods and Results: Thirty-two patients with frequent attacks of paroxysmal AF triggered by PV foci were included. After a transseptal procedure, three 2-french microcatheters and one 7-french catheter for ablation were placed into each of the PVs, and mapping of the four PVs was performed simultaneously. Fifty-eight foci were identified; 51 triggers (88%) originated from the PV and 7 (12%) from atrial tissue. The trigger points of AF were found in a single focus in 14 patients, in 2 foci in 12 patients, and in 3–4 foci in 6 patients. During a mean follow-up period of 10 ± 4 months, ablation eliminated AF without drugs in 86, 50 and 33% of the patients with 1, 2 and 3–4 targeted PVs, respectively; 20 patients (63%) were successfully ablated. Age, history of AF, the dimension of the left atrium and the number of focal origins were significant predictors of success. Conclusion: The technique of simultaneous mapping of PVs using quadruple catheters is a feasible and effective method for mapping the trigger points and ablation of focal AF originating from PVs.