Abstract Objective To evaluate the relationship between asthma control, family income and family costs of asthma in a population of children-adolescents; to detail the family costs of asthma in this age range; and to compare asthma costs for the families of children-adolescents and adults. Methods The authors invited asthmatic subjects who attended a scheduled spirometry test at the Jundiaí School of Medicine (FMJ). The FMJ performs all spirometry tests requested by staff physicians who serve at the public healthcare system in the municipality. Volunteers responded to the ACQ, the Asthma Family Costs Questionnaire and underwent a spirometry test. Results The authors included 342 children-adolescents. Families of children-adolescents taking maintenance therapy and families of those reporting uncontrolled asthma symptoms were more likely to report any expenditure with asthma during the preceding month. In this age range, the smallest expenditures were on diagnostic tests and medical consultations, while home expenditures to avoid asthma triggers were the highest ones. As compared to adults’ families, the children and adolescents families reported a greater proportion of income committed with asthma. Expenditures with transportation to healthcare facilities for asthma care were greater in the families of children-adolescents as compared to the values reported by the adults’ families; in contrast, loss of income due to asthma was smaller in the families of children-adolescents. Conclusions Children-adolescents’ asthma affects the household economy. The authors believe researchers should assess this outcome when designing studies about asthma. Finally, the study's data support the necessity of public policies in low-resource communities to minimize the economic impact of children and adolescents’ asthma.