We assessed the relationship of lower esophageal sphincter pressure (LESP) to presence and absence of lower esophageal mucosal ring (LEMR) in 66 patients to determine if the LEMR was more likely related to prolonged sphincter hypotension. This potential relationship is of interest because LEMR may be due to reflux esophagitis. Each patient had radiographic and manometric studies, and both examinations were done within one week of each other. The mean LESP in patients with LEMR was 23.8 mm Hg (range 4.2-64 mm Hg) compared to 28.7 mm Hg (range 8-59 mm Hg) in patients without LEMR; the difference was not statistically significant. Patients with LEMR were also divided into three subgroups according to the diameter of the rings ( or = 20 mm). There was no significant relationship between the caliber of LEMR and LESP (P > 0.05). Presence of LEMR did not affect the amplitude or duration of primary esophageal peristalsis. These results do not support a relationship between LEMR and prolonged LESP hypotension or abnormal esophageal motility. However, other pathogenetic mechanisms involved in producing reflux esophagitis not related to prolonged sphincter hypotension were not studied.