To determine the relationship between Barrett’sesophagus (BE) and features of ga stroesophageal acid reflux, 24 h esophageal pH monitoring was performed in 90 pa tients. The patients were divided into 3 groups: 31 subjects with BE, 21 with mi ld esophagitis and 38 with severe esophagitis. The following parameters were eva luated: the percentage time of pH<4; the number of reflux episodes over 5 min; t he duration of longest episodes and DeMeester score over total period and the au terior three parameters in erect and supine position . All these parameters in BE were significantly different from those with mild e sophagitis ( P <0.01) and not significantly different from those with severe esophagitis ( P >0.05). During supine position all the above parameters in BE were significantly different from those with reflux esophagitis ( P <0.05). It is concluded that the quantity of acid reflux is not an important factor in development of BE in gastroesophageal reflux (GER), and the acid reflux in supine position might be important in development of BE in GER. The determination of the relationship between Barrett’s pharyngeal (BE) and features of ga stroesophageal acid reflux, 24 h esophageal pH monitoring was performed in 90 pa tients. The patients were divided into 3 groups: 31 subjects with BE, 21 with mi ld esophagitis and 38 with severe esophagitis. The following parameters were eva luated: the percentage time of pH <4; the number of reflux episodes over 5 min; t duration of longest episodes and DeMeester score over total period and the au terior three parameters in erect and All these parameters in BE were significantly different from those with mild e sophagitis (P <0.01) and not significantly different from those with severe esophagitis (P> 0.05). During supine position all the above parameters in BE were significantly different from those with reflux esophagitis (P <0.05). It is said that the quantity of acid reflux is not an important factor in development of BE in gastroesophageal reflux (GER), and the ac id reflux in supine position might be important in development of BE in GER.