Background <p>Peroral endoscopic myotomy (POEM) and diverticular POEM (D-POEM) are important treatments for achalasia and esophageal diverticulum, respectively. Herein, we report the clinical outcomes and long-term effectiveness of bifurcate POEM (B-POEM) for patients with simultaneous achalasia and large epiphrenic esophageal diverticulum (EED), a novel technique combining POEM and D-POEM.</p> Methods <p>We retrospectively collected patients who underwent B-POEM for achalasia and large EED between January 2019 and December 2023. Clinical success was defined as a postoperative Eckardt score of ≤ 3 without additional intervention until the final follow-up in June 2025.</p> Results <p>11 patients who underwent B-POEM were included. The mean diverticular diameter was 67.0 (standard deviation, SD 10.0; range 48.0–83.0) mm, and the mean location was 35.0 (SD 3.4) centimeters from the incisors. The most common achalasia was type I (n = 4, 36.4%). All B-POEM procedures were successful, and the mean procedure time was 81.5 (SD 11.8) min. The mean preoperative Eckardt score was 5.9 (SD 1.3), which significantly decreased to 1.3 (SD 1.0, <i>P</i> &lt; 0.001) at a median follow-up of 28.0 (range 21.0–80.0) months. No cases received additional endoscopic or surgical intervention.</p> Conclusions <p>B-POEM was an effective and safe procedure for patients with achalasia and large EED, which needed further prospective study.</p> Graphical abstract <p></p>