Our study aims to evaluate the presence of adenoid hypertrophy (AH) in children with allergic rhinitis (AR) and the association of AH disease severity and clinical laboratory finding from retrospective, cross-sectional, and nonrandomized trial. The study included 566 children being treated and followed up for allergic rhinitis. Skin prick test for the same allergens was performed for all patients. Adenoid tissue was analyzed by an ENT specialist and the diagnosis was confirmed based on the patient history, endoscopic physical examination and radiology. Adenoid hypertrophy was detected in 118 (21.2 %) of the children with AR. Children with and without AH did not differ statistically and significantly by gender, age, presence of atopy in the family, exposure to smoke (p > 0.05). Comparison of the groups for AR duration demonstrated significantly higher frequency of persistent rhinitis in patients with AH (p < 0.05). Of the AR patients with AH, 90 (76.3 %) had moderate-severe rhinitis and 274 (62.6 %) AR patients without AH had moderate-severe rhinitis (p = 0.005). Itchy nose was more frequent in AR patients without AH, and nasal congestion was more common in AR patients with AH (p = 0.017 and p = 0.001, respectively). The presence of asthma was more common among AR patients without AH (p = 0.037). Intergroup comparisons for presence of atopic dermatitis, the percentage of eosinophil, serum IgE levels, the number of positive sensitivity, polysensitization, sensitivity to house dust mite, cockroach, pollens and dander yielded no significant difference (p > 0.05). On the other hand, sensitivity to Alternaria alternata was significantly more frequent in AR patients with AH (p = 0.032). The presence of AH increased the severity of the disease and prolongs disease duration. There was a negative relationship between AH and asthma in children with AR. AH is more common among children with mold sensitivity. AH should be considered and investigated particularly in non-asthmatic children with pronounced nasal congestion and A. alternata sensitivity.