An association between chronic sinusitis and asthma has been noted for many years, although the precise nature of the relationship is poorly understood. Earlier studies, using traditional surgical techniques, have demonstrated subjective improvement in asthmatic complaints. Reports demonstrating improvement following endoscopic sinus surgery for chronic sinusitis are rare. To report our experience with endoscopic sinus surgery and asthmatics, we reviewed the charts of 75 consecutive patients with asthma and chronic sinusitis who underwent endoscopic sinus surgery between 1994 and 1996. Study criteria included the following: chronic sinusitis, one year preoperative and one year postoperative follow-up from endoscopic sinus surgery, and asthma requiring inhaled steroids and oral prednisone for control. Many patients required prednisone bursts for control of asthma. Number of days and total dose of oral prednisone were used as objective measures of asthma control. Number of weeks of antibiotics was used as a relative measure of sinusitis. Fourteen of the 15 patients meeting study criteria decreased their postoperative prednisone requirement by total number of days (preoperative 84 versus postoperative 63 days [p < 0.0001]). Postoperatively, patients required an average of 1300 mg less oral prednisone (p < 0.033). Antibiotic use also decreased, with an average use of antibiotic nine weeks preoperatively versus seven weeks postoperatively (p < 0.045). This study provides corroborative objective evidence that, at least in the short term, endoscopic sinus surgery is efficacious in the management of patients with chronic sinusitis and asthma.