There is no evidence-based treatment for persistent dysphagia after laparoscopic fundoplication. The aim of this study was to evaluate the effect of pneumatic dilation on persistent dysphagia after laparoscopic fundoplication.We performed a multicentre, single-blind, randomised sham-controlled trial of patients with persistent dysphagia (>3 months) after laparoscopic fundoplication. Patients with an Eckardt symptom score ≥4 were randomly assigned to pneumatic dilation (PD) using a 35 mm balloon or sham dilation. Primary outcome was treatment success, defined as an Eckardt score <4 and a minimal reduction of 2 points in the Eckardt score after 30 days. Secondary outcomes included change in stasis on timed barium oesophagogram, change in high-resolution manometry parameters and questionnaires on quality of life, reflux and dysphagia symptoms.Forty-two patients were randomised. In the intention-to-treat analysis, the success rates of PD (7/21 patients (33%)) and sham dilation (8/21 patients (38%)) were similar after 30 days (risk difference -4.7% (95% CI (-33.7% to 24.2%) p=0.747). There was no significant difference in change of stasis on the timed barium oesophagogram after 2 min (PD vs sham: median 0.0 cm, p25-p75 range 0.0-4.3 cm vs median 0.0 cm, p25-p75 range 0.0-0.0; p=0.122) or change in lower oesophageal sphincter relaxation pressure (PD vs sham: 10.54±6.25 vs 14.60±6.17 mm Hg; p=0.052). Quality of life, reflux and dysphagia symptoms were not significantly different between the two groups.Pneumatic dilation with a 35 mm balloon is not superior to sham dilation for the treatment of persistent dysphagia after fundoplication.