Patients with sigmoid-type achalasia can be challenging to treat with per-oral endoscopic myotomy (POEM). A short myotomy improves technical success, however outcomes have not previously been evaluated METHODS: This was a multicenter, international, retrospective study of patients who underwent POEM with short (≤ 4 cm) or standard esophageal myotomy. Outcomes included clinical and technical success, procedural adverse events, and reflux rates. A total of 109 patients with sigmoid achalasia (sigmoid = 74, advanced sigmoid = 35) underwent POEM across 13 centers (Short myotomy = 59, standard = 50). Technical success was 100% across both groups. Patients who underwent short myotomy had a significantly shorter mean procedure time (57.7 ± 27.8 vs 83.1 ± 44.7 minutes, p = 0.0005). A total of 6 AEs were recorded in 6 patients (5.5%; 4 mild, 2 moderate); AE rate was not significantly different between short and standard groups. Ninety-eight patients had follow-up data (median = 3.6 months [IQR, 1-14]) months). Clinical success was 94% (short = 93%; standard = 95%, p = 0.70) and did not differ based on achalasia subtype or sigmoid achalasia severity. Twenty-one (22%) patients reported post-POEM reflux and 44% (16/36) had objective evidence of pathologic reflux. Rates of pathologic reflux were significantly increased in the standard vs short group (OR 18.0 [95% CI: 2.0 - 159.0]; p = 0.009). POEM with short myotomy is effective and safe for the short-term treatment of sigmoid and advanced sigmoid achalasia. Short myotomy may lead to less reflux than standard myotomy.