The objectives of this study were to investigate the efficacy of leukotriene receptor antagonists in the treatment of perennial allergic rhinitis. The study was designed as a randomized, 14-day treatment to compare the efficacy of zafirlukast, loratadine, and the combination of loratadine and pseudoephedrine in the treatment of perennial allergic rhinitis. Rhinitis symptom scores, acoustic rhinometry, and rhinomanometry were used to evaluate the efficacy. The results showed that after a 14-day treatment period, patients in all treatment groups had a lower mean score for the symptoms of rhinorrhea, nasal itching, and nasal obstruction (p < .05). Patients who took zafirlukast did not report a significant decrease in sneezing score (p = .1456), but the decrease in nasal obstruction score was more pronounced than in those who took loratadine or loratadine- pseudoephedrine (p = .014). However, the results of acoustic rhinometry and rhinomanometry did not have a significant difference among the three groups (p > .05). The study concluded that zafirlukast seemed to have a better effect on relieving the symptom of nasal obstruction in patients with perennial allergic rhinitis, but the actual mechanism needs further investigation.