Many clinicians now recognize the importance of incorporating an assessment of health-related quality of life (HRQL) into their clinical studies and practice. Conventional clinical measures provide valuable information about the status of the affected organ system, but they rarely capture the functional impairments (physical, emotional, and social) that are important to the patients in their everyday lives. In order to obtain a complete picture of a patient's health status, both the conventional clinical indices and the patient's HRQL must be measured. Both adults and children with asthma and rhinitis are distressed by the symptoms, and they are limited in their day-to-day activities such as sports, work or school work, and participation in other activities with friends. In addition, both adults and children experience emotional strain as a result of both conditions. Disease-specific HRQL questionnaires have been developed and validated for both adults and children with asthma and rhinitis. These questionnaires have good measurement properties and validity and can be used in both clinical trials and clinical practice to assess the impact of the condition on a patient's life. Since one of the aims of treatment is to ensure that patients benefit from it, an essential component of clinical assessment should be an evaluation of HRQL.