The achalasia is a rare disease in children; the patients less than 14 years of age acount for only 2% of over-all incidence of achalasia. The achalasia is slowly preogressing, and dysphagia is typical symptom of the disease. The definite diagonsis of achalasia can be made with esophageal manometry. The achalasia can be treated by either ballon dilatation or surgical correction. The necesity of fundoplication to prevent the complication oif gastroesophageal reflux is still the subject of controversy. In pediatric patients, it has been a rule that the surgical correction should be undertaken after the definite diagnsosis was made with esophageal manometric study. We experienced a 3 1/2 year female patient received with the surgical tratment consisted of Modified heller's Myotomy and Dor's anterior fundoplication through the abdominal approach, and the result was satisfactory.