The objective of this study was to compare the effectiveness of montelukast combined with loratadine once daily to loratadine alone for a 2-week treatment course of allergic rhinitis in a randomized, double-blind pla-cebo controlled trial which enrolled 115 children, 6-15 years old. The patients were randomly assigned to receive montelukast and loratadine (treatment group) or placebo and loratadine (control group). The primary outcome was the mean percent change of the total daytime nasal symptom scores (PDTS) and secondary outcomes were the mean percent changes of the nighttime nasal, daytime eye and composite symptom scores (PNTS, PES, PCS), as well as the nasal secretion , turbinate swelling and nasal congestion scores (PNSS, PTSS, PNCS). There were no significant differences in the PDTS of the 2 groups. The change in the night time nasal congestion score (PNTS-congestion) was higher in the treatment group, but not statistically significant (p = 0.077). Only the mean percent change in decreased turbinate swelling was significantly greater in the montelukast and loratadine group than the loratadine alone group (-22 ± 7 vs. -1 ± 5, p < 0.05).