Objective: To investigate the efficacy of endoscopic sinus surgery (ESS) in the management of chronic sinusitis and asthma in patients with nasal polyps and steroid-dependent asthma. Study Design: Retrospective chart review. Methods: The study included 17 patients who underwent ESS with nasal polyps, steroid-dependent asthma with or without aspirin sensitivity and a minimum of 1 year postoperative follow-up. Nine patients were ASA sensitive, and eight patients were ASA tolerant. Chronic sinusitis and asthma were evaluated using subjective (patient complaints) and objective (computed tomography scans, pulmonary function tests, steroid doses) criteria. Preoperative data were compared with data obtained 12 to 18 months postESS. Tissue samples were graded for degree of inflammation and edema. Results: Thirteen of the 17 (76.5%) patients reported improved clinical symptoms postESS. The postoperative Lund-Mackay scores were statistically lower for the 17 patients (P < .0001). The group experienced improvement in postoperative forced expiratory volume at 1 second (FEV1) (P < .014). Twelve of 17 (70.6%) experienced reduction in systemic steroid usage (P < .048). The ASA sensitive patients did not have a statistical improvement in postoperative FEV1 (P > .08) and sinonasal symptoms (P > .16) compared with the ASA tolerant group. Polyp tissue from the ASA sensitive patients demonstrated more edema and more inflammation on average than ASA tolerant polyps, but the results were not statistically significant. Conclusion: ESS demonstrates a beneficial effect on the sinonasal and asthma symptomatology in patients with nasal polyps and asthma using objective measures. Subset of aspirin-tolerant patients have statistically better outcome for sinonasal symptoms and pulmonary function testing than aspirin-sensitive patients.