Systemic sclerosis (SSc) is a connective tissue disorder which frequently involves the esophagus, with severe gastroesophageal reflux (GER) and dysphagia as clinical consequences of esophageal dysmotility. The relationship between the severity and extent of esophageal acid exposure and the specific manometric disturbances has received little attention. Similarly, a paucity of manometric data exists regarding pharyngeal/upper esophageal sphincter (UES) function in SSc patients. We prospectively studied 36 SSc patients using computerized solid-state manometric and ambulatory dual-pH (upper and lower esophageal) monitoring, to define further the relationship between esophageal dysmotility and severity of GER in these patients. Patients were separated for analysis into two subgroups based on the absence (group 1, N = 25) or presence (group 2, N = 11) of distal esophageal peristalsis. SSc disease variant (diffuse vs. limited) and duration of illness were inaccurate predictors of the presence and severity of esophageal involvement. The mean lower esophageal sphincter (LES) pressure for the SSc patients (15.8 +/- 1.2 mm Hg, mean +/- SE) was significantly lower (p < 0.01) than that for a control group (26.0 +/- 2.1 mm Hg). There was no significant difference between the mean LES pressure for group 1 (15.0 +/- 1.6 mm Hg) and group 2 (17.5 +/- 1.6 mm Hg) patients. Although distal esophageal aperistalsis was noted in 70% of patients, normal proximal esophageal contraction pressures were documented in all cases. Mean UES pressure was significantly (p < 0.01) lower in group 1 (52.5 +/- 4.6 mm Hg) than in group 2 (80.5 +/- 10.6 mm Hg). The mean duration of UES relaxation and the mean time interval between the onset of UES relaxation and onset of pharyngeal contraction were significantly (p < 0.05) shorter for group 1 than group 2 patients. Pharyngeal pressures, peristalsis, and other aspects of pharyngeal/UES coordination were normal. Excessive distal esophageal acid exposure was often seen in patients in both subgroups, but it was significantly (p < 0.01) greater in group 1. Excessive proximal esophageal acid exposure was documented only in patients with absent distal peristalsis. Linear regression analysis revealed a poor correlation between the severity of esophageal acid exposure and the LES pressure. Thus, the severity and extent of GER in SSc is most closely related to the integrity of distal esophageal peristalsis.