context: helicobacter pylori has been associated with worsening of gastroesophageal reflux disease (gerd). objective: to evaluate the effect of h. pylori eradication in gerd patients. methods: we conducted a prospective, randomized, controlled trial performing symptom evaluation, endoscopy, histology, manometry and esophageal ph testing on gerd patients. patients infected with h. pylori were randomized to: 1) eradication treatment plus proton pump inhibitors treatment, or 2) proton pump inhibitors alone. patients not infected constituted a negative control group. after 3 months, patients were re-evaluated by symptom assessment, endoscopy, histology and manometry. results: gerd treatment resulted in significantly higher lower esophageal sphincter pressure, as measured by mean expiratory pressure, in h. pylori negative patients. there was significantly lower proportion of hypotensive waves and significantly higher proportion of normotensive waves in non-eradicated patients. all symptom scores were significantly reduced in the post-treatment period compared to baseline, to values that were similar among the three groups, in the post-treatment period. in the post-treatment period, erosive esophagitis was significantly less frequent on those not eradicated. conclusion: manometric, clinical and endoscopic data showed no benefit in eradicating h. pylori in gerd. our data supports the hypothesis that h. pylori eradication does not influence gerd.