BACKGROUND: In the evaluation of several endoscopic antireflux procedures, a discrepancy in the degree of improvement between symptoms and objective reflux parameters as measured by pH-metry has been reported. AIM: To assess the additional value of impedance monitoring in the evaluation of endoscopic gastroplication for gastro-oesophageal reflux disease. METHODS: Eighteen patients with gastro-oesophageal reflux disease were treated with three endoscopic gastroplications, and underwent 24 h pH-impedance monitoring before and 3 months after treatment. RESULTS: Total reflux exposure time as assessed by pH-metry and impedance monitoring was significantly decreased after treatment (P = 0.047 and <0.001, respectively). When assessed with impedance monitoring, the mean number of reflux episodes was significantly decreased after the procedure (82 vs. 56, pre vs. post, P < 0.001). Furthermore, the mean numbers of liquid and acid reflux episodes in patients with symptomatic improvement were significantly reduced after treatment (P = 0.04 and 0.02, respectively). After treatment, mean volume clearance time (s) and mean number of proximal reflux episodes were significantly decreased (P < 0.001 and 0.002, respectively). CONCLUSIONS: Impedance monitoring can identify the specific effect of endoscopic gastroplication on the different types of reflux episodes with regard to gas-liquid composition and pH, as well as on volume clearance and the proximal extent of the refluxate.