Background: Safer and less time-consuming alternatives to single-blind placebo-controlled oral challenge (SBPCOC) have been sought for the diagnosis of aspirin-exacerbated respiratory disease (AERD). Nasal challenges with various nonsteroidal anti-inflammatory drugs and assessment methods have been developed. Objective: Our objective was to evaluate the utility and safety of nasal ketorolac challenge (NKC) using acoustic rhinometry in patients with suspected AERD. Methods: The study population comprised 36 patients with suspected AERD. NKC was performed with placebo (saline) and 13 mg of ketorolac sprayed as aerosol into both nostrils. A positive challenge result was defined as an increase of ≥30% in nasal symptoms (recorded using a visual analog scale) and a 30% drop in the sum of the volumes of both nasal cavities at 2-8 cm. Patients with a negative NKC result underwent SBPCOC with aspirin (cumulative dose of 750 mg). Results: A naso-ocular reaction during NKC was detected in 21 patients. Four patients also developed mild asthma exacerbations (although only 1 experienced a decrease in FEV 1 >15%). No other significant adverse events occurred. The remaining 15 patients with a negative NKC result had a negative response during aspirin SBPCOC. Conclusion: NKC assessed using acoustic rhinometry is a reliable method for the study of patients with AERD. We suggest that NKC assessed with acoustic rhinometry was useful and safe for selection of candidates for safe oral aspirin challenge.