Background and Aims: This study aimed to assess the level of the expression of CCL-18 on nasal inferior turbinate mucosa in patients with mild (M) and moderate-to-severe (M/S) persistent allergic rhinitis (PAR). Methods: The participants in this case-controlled study were divided into three groups: patients with M/S PAR, patients with M PAR, and the healthy control group. Biopsies of nasal inferior turbinate mucosa were obtained from the participants. Expression of CCL-18 mRNA was evaluated by real-time PCR. The serum levels of CCL-18 were determined by ELISA. Total serum IgE levels and specific serum IgE levels were measured. The clinical manifestations were assessed using the total nasal syndrome score (TNSS). Results: Gene expression and the serum level of CCL-18 in patients with M/S PAR increased significantly compared to the control group and patients with M PAR. The serum level of CCL-18 was found to correlate with TNSS in patients with M/S PAR. There was a statistical correlation between the serum level of CCL-18 and the total serum IgE in the treatment groups. Conclusion: The results of the study indicate that there could be a relationship between the expression of CCL-18 in nasal turbinate mucosa and the severity of allergic rhinitis