Patients with gastro-oesophageal reflux disease (GORD) commonly report waking up in the morning with a sour or bitter taste in their mouth. The aim of the study was to compare the prevalence and frequency of acid reflux events prior to and immediately after awakening from sleep in the morning between GORD patients and normal subjects. Thirty-nine patients with heartburn at least three times a week and abnormal pH test and nine healthy controls were included. All subjects were evaluated by demographic and GORD Symptom Checklist questionnaires. Subjects underwent pH testing concomitantly with actigraphy. A novel technology that simultaneously integrates raw actigraphy and pH monitoring data was utilized to determine the presence, frequency, and characteristics of acid reflux events prior to (up to 1 h) and immediately after (10 and 20 min) awakening from sleep in the morning. Nineteen (48.7%) of the GORD patients had an acid reflux event within the first 20 min after awakening from sleep in the morning as compared to only seven (17.9%) during the hour prior to awakening. Within the first 10 and 20 min after awakening, patients had a total of 32 and 60 acid reflux events, respectively, as compared to 14 during the 1 h prior to awakening (P < 0.05). None of the healthy control patients demonstrated any reflux events during these three studied periods (P < 0.001). Riser's reflux is very common among GORD patients and possibly may explain reports of early-morning GORD symptoms.