Thirty-five consecutive adult patients with paroxysmal laryngospasm (LS) and with unimpaired vocal fold mobility were prospectively studied for coexisting gastroesophageal reflux disease (GERD). Nineteen patients reported frequent (>3 episodes a week) LS episodes (FLS patients) and 16 patients reported occasional LS episodes (OLS patients). All patients underwent an extensive otorhinolaryngological (ORL) examination, upper gastrointestinal (GI) endoscopy, ambulatory 24-hr dual-channel esophageal pH monitoring, and esophageal manometry. In addition, a subset of LS patients also underwent ambulatory duodenogastroesophageal reflux (DGER) monitoring. Patients with daily LS used the symptom marker during pH monitoring indicating separate LS episodes. All FLS patients and 14 OLS patients (87%) had a diagnosis of GERD. Only 10 patients (29%) experienced heartburn and/or regurgitation. Compared to OLS patients, FLS patients generally had more severe GERD as indicated by a higher prevalence of a hiatus hernia, higher distal and proximal esophageal acid exposure times, and higher values of DGER. In six FLS patients, 21 LS episodes (91%) occurred simultaneously with acid reflux, indicating a causal association between LS and GER. On antireflux therapy consisting of omeprazole, 20 mg bid, or lansoprazole, 30 mg oid, and lifestyle measures, LS ceased completely in all patients within 6 weeks. The present study not only demonstrates the role of GER in the pathogenesis of LS and the effectiveness of antireflux therapy, but also suggests that LS in adult patients with unimpaired vocal fold mobility might be considered a typical, although most frequently unrecognized, supraesophageal manifestation of GER.