ABSTRACT Objective: To evaluate the impact of pediatric asthma on patients of a specialized outpatient clinic in Southern Brazil. Methods: The study included children aged 8 to 17 years old with asthma diagnosis (mild, moderate and severe) under treatment at the asthma clinic of Hospital São Lucas da Pontifícia Universidade Católica do Rio Grande do Sul (PUCRS), Brazil. Measurements of spirometry, quality of life, disease control and atopy tests were applied. Results: A total of 66 children were included in the study and divided into groups, according to the severity of the disease: mild, moderate or severe asthma. The results showed similarities in both the treatment and the impact of asthma between groups, except for adherence to treatment: the group with mild asthma showed least adherence to treatment, and the group with severe asthma, greater adherence (p=0.011). As to school absenteeism, the group with severe asthma showed higher frequency (p=0.012), with over 10 days per year (p=0.043). Spirometry showed lower volume/capacity for the group with moderate asthma, followed by the groups with severe and mild asthma. All groups had a high prevalence of allergic asthma, with mites as the main allergens. For quality of life (QOL), and health-related quality of life (HRQOL) levels, there were no differences between groups. In addition, the values were close to the acceptable levels for the total score and for each one of the six domains. The same occurred for the HRQOL-asthma module. Conclusions: QOL and HRQOL present acceptable levels regardless of the severity of the disease.