Introduction Oesophageal hypomotility (OH) disorders are characterised by a decrease in the vigour of distal oesophageal contractions. An estimated 21 to 49% of patients with pathological gastroesophageal reflux (GOR) also have associated OH. However, prevalence of pathological GOR in OH who do not present with reflux symptoms has not been characterised. Overlooked reflux in these patients may hamper the success in treatment and also increase the risk of long-term side effects from chronic reflux. The aim of this study was to investigate the prevalence of pathological GOR and clinical presentation of patients with severe OH who do not present typical gastroesophageal reflux disease (GORD) symptoms. Method All patients diagnosed with frequent failed peristalsis or absent peristalsis on oesophageal high resolution manometry during January 2013 – December 2014 were selected retrospectively. Exclusion criteria were having typical reflux symptoms (heartburn and/or regurgitation) and history of antireflux surgery. All patients underwent ambulatory 24 h reflux monitoring. pH cut off 4 was used and pathological GOR was defined as high acid exposure time (total >6.3%, supine >1.2%, upright >4.2%)1and/or high number of reflux events >73. Symptoms were reported by the patient during interview. P value Results In total, 78 patients (30 male, 48 female; mean age 55 [19–82]) were included. Pathological GOR was detected in 28/78 (36%) of the patients [abnormal acid exposure time: 12/78 (15%) upright, 11/78 (14%) supine, 12/78 (15%) total, abnormal number of reflux events 15/78 (19%)]. The most common symptoms in patients with pathological GOR: dysphagia 21/28 (75%), chest pain 11/28 (39%) and cough 9/28 (32%) and in patients without GOR: epigastric pain: 19/50 (38%), chest pain 18/50 (36%), dysphagia 16/50 (32%). Epigastric pain was more commonly reported in patients without pathological GOR (P Conclusion Pathological GOR is prevalent in one third of the patients with severe OH without typical GORD symptoms. Reflux monitoring maybe indicated in patients with severe OH regardless of their presenting symptoms. Disclosure of interest None Declared. Reference Johnson LF, DeMeester TR. Twenty-four-hour pH monitoring of the distal esophagus. A quantitative measure of gastroesophageal reflux. Am J Gastroenterol. 1974:62:325–332.