Intraoperative manometry has been proposed as a supportive procedure during the execution of anti-reflux operations and in the surgical treatment of achalasia. This procedure is not necessary in preparing anti-reflux plasty such as Belsey or Nissen, the outcome of which depends mostly on the correct execution of the surgical technique. Utilization of intra-operative manometry provides considerable benefits during the surgical treatment of achalasia, both when executing the extra-mucous myotomy and for the correct preparation of the anti-reflux plasty according to Dor, which is associated to it. Manometric control has made it possible to define the various anatomical components that, at both the esophageal and gastric levels, constitute the area which functionally corresponds to the lower esophageal sphincter and therefore a correct execution of the myotomy. As demonstrated by the follow-up study of our surgical patients, the intraoperative manometric measurement of the strain and of the length of the anti-reflux plasty is the determining factor affecting outcome over time. The pressure is apt to decrease even 5 year after surgery; maintaining given length and strain standards when executing the plasty can prevent delayed complications, such as esophagitis from gastro-esophageal reflux.