This study aims to evaluate by the use of 24-hour combined multichannel intraluminal impedance and pH monitoring (MII-pH) the efficacy of the Nissen fundoplication in controlling both acid and nonacid gastroesophageal reflux (GER) in patients that underwent Heller myotomy for achalasia. It has been demonstrated that fundoplication prevents the pathologic acid GER after Heller myotomy, but no objective data exists on the efficacy of this antireflux surgery in controlling all types of reflux events. The study population consisted of 20 patients that underwent laparoscopic Heller myotomy and Nissen fundoplication for achalasia. All patients were investigated with manometry and MII-pH. MII-pH showed no evidence of postoperative pathologic GER. The overall number of GER episodes was normal in both the upright and recumbent position. This reduction was obtained because of the postoperative control of both the acid and nonacid reflux episodes. The Nissen fundoplication adequately controls both acid and nonacid GER after extended Heller myotomy. Further controls with MII-pH are warranted to check at a longer follow-up for the efficacy of this antireflux procedure in achalasic patients.