Background and objective: The two-spotted spider mite (Tetranychus urticae, TSM) is the most common mite infesting fruit leaves and herbaceous plants. Recent investigations have revealed that these mites play an important role in the development of asthma and rhinitis in apple farmers and exposed adults. The aim of this study is to evaluate sensitization to TSM in children living around pear orchards and its relationship with prevalence of allergic diseases. Subjects and methods: A total of 2,584 children living around pear orchards was recruited for this study. The subjects responded to a questionnaire, and underwent skin-prick testing to common inhalant allergens including TSM. RESULTS: The prevalence of asthma based on the questionnaire was 6.9% in 7 to 12-year-old subjects and 6.4% 13 to 18-year-old subjects. The prevalence of chronic rhinitis based on the questionnaire was higher in subjects 13-18 years old than in those 7-12 years old (24.8% vs. 21.2%). On the skin prick tests, the most common sensitizing indoor allergen was D. pteronyssinus (28.3%), followed by D. farinae (27.2%), T. putrescentiae (13.5%), and cockroach (10.9%). The sensitization rate to TSM was higher in the older children than in the younger ones (12.2% vs. 6.0%). While sensitization to TSM was not associated with prevalence of asthma among the younger children, the prevalence of asthma was higher in the older children sensitized to TSM than in those without sensitization (8.5% vs. 5.5%). However, the sensitization to TSM was not associated with the prevalence of chronic rhinitis in both groups. CONCLUSION: TSM is a common sensitizing allergen in children living around pear orchards, and the sensitization to TSM is significantly associated with the prevalence of asthma in older children.