Zenker's diverticulum (ZD) per-oral endoscopic myotomy (Z-POEM) is an effective treatment for symptomatic (ZD). A modification to Z-POEM is the mucosal flap incision (MFI). We describe the technical and clinical success of patients who underwent Z-POEM with MFI. We included patients who underwent Z-POEM with MFI for ZD at 8 international centers. The primary outcome was the rate of clinical success, assessed by post-procedure Kothari-Haber symptom score (KHSS) without retreatment. Secondary outcomes included technical success, serious adverse events, and clinical recurrence with need for retreatment. 36 patients (69% male, age 69 + 9 years) underwent Z-POEM with MFI for symptomatic ZD. Mean ZD size was 32 mm (+ 14). Clinical success was achieved in 35 (97%) cases. Median pre-procedure KHSS was 6 and median post-procedure KHSS was 1 (P <0.0001). Technical success was achieved in all cases. Mean procedure time was 57 minutes (+ 32), median follow up time was 196 days (IQR 39-499). There was one adverse event (3%) which was treated endoscopically. Z-POEM with MFI has a high rate of technical and clinical success. Prospective evaluation is needed to further validate this technique in patients with large ZD.