Background: Allergic reactions resulting from exposure to environmental allergens are responsible for problems such as asthma and allergic rhinitis. House dust mites (HDMs) are one of the most important causes of allergic sensitization and a major source of allergens worldwide. Objective: To investigate associations between the presence of HDMs in the homes of adolescents aged 13 to 14 years and the prevalence of respiratory problems using the International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire. Methods: A total of 103 adolescents from the city of Lajeado, south of Brazil, participated in the ISAAC Protocol, and 10 homes were sampled for dust collection. Results: Regarding the medical history of asthma and rhinitis, a prevalence of 14.7% of asthma was found, and 68.9% of the adolescents have already had rhinitis. The investigation of active asthma and rhinitis showed that 5.15% of adolescents had symptoms of asthma and 39.14% had symptoms of allergic rhinitis. Premature birth, low birth weight and smoking mother were shown to be risk factors for the development of asthma and allergic rhinitis. HDMs were mostly found on the carpet (46.80%), followed by bed (34.04%) and sofa (14.89%); curtains had the fewest mites (4.25%). Dermatophagoides pteronyssinus (46.0%) and Dermatophagoides farinae (31.91%) were the most frequently found species. Conclusion: The homes of adolescents with respiratory problems had a large number of HDMs.