Much discussion is taking place regarding the role of gastric reflux disease in the development and maintenance of chronic sinus disease. We studied 31 patients in a large urban private practice who had recalcitrant chronic sinusitis despite aggressive medical and surgical therapy. After we obtained information on the severity of each patient's sinus disease, we performed either double- or triple-catheter probe pH testing to assess the presence of reflux disease. Of the 30 patients who were successfully tested (1 patient did not tolerate probe testing), 25 demonstrated reflux disease, including 2 whose reflux reached the level of the nasopharynx. These 25 patients were placed on a proton-pump inhibitor (PPI) regimen and reassessed at least 1 month later. At follow-up, 14 of 15 evaluable patients demonstrated at least some improvement in their sinus symptoms, including 7 who experienced either a complete or almost-complete resolution of symptoms. The improvements in sinus symptoms corresponded with improvements in reflux symptoms. These findings suggest that antireflux therapy might play a role in the treatment of recalcitrant chronic sinus disease.