Objective To detect the effect of longterm lowdose clarithromycin in the treatment of pediatric chronic rhinosinusitis (CRS). Methods 74 patients with pediatric CRS were randomly divided into clarithromycin group (36 cases) and control group (38 cases). The patients in the control group received a 12week treatments of alkaline nasal douche, and intranasal momestasone furoate. The patients in clarithromycin group received a 12week treatments of clarithromycin, alkaline nasal douche and intranasal momestasone furoate. All patients underwent assessment of visual analogue score (VAS) and nasal endoscopy before and after the treatment. There were four time points for assessment including start time of the treatment, 4 weeks, 8 weeks and 12 weeks after the treatment. Results At 4 weeks after the treatment, the scores of VAS and endoscopic parameters in both groups got improved with the no significant difference (P>0.05). At 8 weeks and 12 weeks after the treatment, further improvement was all achieved in the scores and parameters, and the difference between the two groups was significant (P<0.01). In additon, CT examination at 12 weeks after the treatment showed that the improvement in the clarithromycin group was greater that in the control group (P<0.01). Conclusion With good therapeutic effect and safety, longterm, lowdose clarithromycin may be a valid alternative for pediatric CRS