Abstract Aims The left atrial posterior wall is a potential ablation target in patients with recurrent atrial fibrillation despite durable pulmonary vein isolation or in patients with roof-dependent atrial tachycardia (AT). Pulsed-field ablation (PFA) offers efficient and safe posterior wall ablation (PWA), but available data are scarce. Methods and results Consecutive patients undergoing PWA using PFA were included. Posterior wall ablation was performed using a pentaspline PFA catheter and verified by 3D-electroanatomical mapping. Follow-up was performed using 7-day Holter ECGs 3, 6, and 12 months after ablation. Recurrence of any atrial arrhythmia lasting more than 30 s was defined as failure. Lesion durability was assessed during redo procedures. Posterior wall ablation was performed in 215 patients (70% males, median age 70 [IQR 61–75] years, 67% redo procedures) and was successful in all patients (100%) by applying a median of 36 (IQR 32–44) PFA lesions. Severe adverse events were cardiac tamponade and vascular access complication in one patient each (0.9%). Median follow-up was 7.3 (IQR 5.0–11.8) months. One-year arrhythmia-free outcome in Kaplan–Meier analysis was 53%. A redo procedure was performed in 26 patients (12%) after a median of 6.9 (IQR 2.4–11) months and showed durable PWA in 22 patients (85%) with only minor lesion regression. Among four patients with posterior wall reconnection, three (75%) presented with roof-dependent AT. Conclusion Posterior wall ablation with this pentaspline PFA catheter can be safely and efficiently performed with a high durability observed during redo procedures. The added value of durable PWA for the treatment of atrial fibrillation remains to be evaluated.