UNLABELLED BACKGROUND Although Heller myotomy is one of the most effective treatments for achalasia, it may be associated with early or late symptom relapse in some patients. Therefore, additional treatment is required to achieve better control of symptoms. AIM To evaluate the safety and efficacy of pneumatic balloon dilation (PBD) in patients with symptom relapse after Heller myotomy. METHODS Thirty six post-myotomy patients were evaluated from 1993 to 2013. Six patients were excluded from the analysis because of comorbid diseases or epiphrenic diverticula. Thirty patients were treated with PBD. Primary outcome was defined as a decrease in symptom score to 4 or less and a reduction greater than 80% from the baseline in the volume of barium in timed barium esophagogram in 6 weeks. Achalasia symptom score (ASS) was assessed at 1.5, 3, 6, and 12 months after treatment and then every six months in all patients and PBD was repeated in case of symptom relapse (ASS>4). RESULTS The mean age of the patients was 45.5±13.9 years (range: 21-73). Primary outcome was observed in 25 patients (83%). The mean ASS of the patients dropped from 7.8 before treatment to 1.3±2.0 at 1.5 months after treatment (p=0.0001). The mean volume and height of barium decreased from 43.1±33.4 and 7.1±4.7 to 6.0±17.1 and 1.1±2.2, respectively (p=0.003, p=0.003). The mean duration of follow-up was 11.8±6.3 years. At the end of the study, 21 patients (70%) reported sustained good response. No major complications such as perforation or gross bleeding were seen. CONCLUSION PBD is an effective and safe treatment option for achalasia in patients with symptom relapse after Heller myotomy.