Introduction: Achalasia is the most common primary motor disorder of the esophagus. Its reported incidence is low, even more in pediatric patients. Laparoscopic Heller myotomy is the current standard of treatment. During the last years, per-oral endoscopic myotomy (POEM) has been positioned as a safe and effective therapeutic alternative as the Heller procedure for esophageal achalasia. Objective: To describe the POEM technique and report the first pediatric case in our country. Clinical Case: 11-year-old patient, previously healthy, who presented with progressive dysphagia for solids and liquids and weight loss. The study concluded a type II achalasia. The patient underwent a POEM and had a postoperative course without incidents. One year after the intervention, symptomatic, endoscopic and manometric resolution have been documented. Conclusions: The described case is the first POEM in a pediatric patient in our country. Esophageal achalasia is uncommon in pediatrics and POEM has demonstrated clinical success and safety comparable to laparoscopic Heller myotomy in short and medium term. Long-term follow-up will determine its definitive role in the treatment of pediatric patients with esophageal achalasia.