Background: Although both nasal steroids and macrolide antibiotics have been recommended for the treatment of chronic rhinosinusitis without nasal polyps (CRSsNPs), whether there is any difference in their clinical efficacy remains unexplored. In addition, few studies have investigated their clinical efficacy in a Chinese population living in China, who present distinct inflammatory patterns compared with white patients in western countries. This study compares the efficacy of mometasone furoate and clarithromycin treatment in CRSsNP in Chinese adults in a preliminary prospective, open-label, randomized trial. Methods: Forty-three CRSsNP patients were randomized to receive mometasone furoate nasal spray at 200 mu g (n = 21) or clarithromycin tablet at 250 mg (n = 22) once daily for 12 weeks. Patients were assessed before the treatment and after 4, 8, and 12 weeks after treatment. Subjective symptoms were scored on a visual analog scale. Endoscopy physical findings were scored according to Lanza-Kennedy scoring system. Moreover, smoking and atopic status and coexistence of allergic rhinitis (AR) and asthma were recorded. Results: Before the treatment, no significant difference in symptoms and nasal endoscopic physical findings were found between mometasone furoate and clarithromycin group. As early as 4 weeks after dosing, a significant reduction of total symptom scores, nasal obstruction, headache, rhinorrhea and overall burden scores, and mucosal swelling and nasal discharge scores were observed in both groups. No significant difference in symptom or endoscopic scores was observed between these two groups at any posttreatment observation time point. The coexistence of AR was correlated with lower scores of mucosal edema and nasal secretion in the mometasone furoate group after 12-week treatment. Conclusion: Mometasone furoate and clarithromycin show a comparable clinical effect for CRSsNPs in Chinese adults. Mometasone furoate is more effective in improving edema and secretion for CRSsNP patients with concomitant AR. (Am J Rhinol Allergy 25, e203-e207, 2011; doi:10.2500/ajra.2011.25.3728)