BackgroundTRACK (Test for Respiratory and Asthma Control in Kids) questionnaire is an instrument developed and validated in English to evaluate the control of respiratory symptoms in children under 5 years of age.ObjectiveTo validate the Portuguese version of the TRACK questionnaire.MethodsThe validation was done in an observational, prospective and multicenter evaluation (six centers in Brazil) in children with recurrent respiratory symptoms. Children were classified according to symptoms, GINA criteria and medical evaluation. Parents and doctors rated child respiratory symptom control in the last month (VAS). Approval from the Institutional Review Board was obtained in each centre, and written informed consent was obtained from parents.ResultsData from 299 children were obtained at baseline, and 195 at follow-up. The median score of the TRACK questionnaire was 65 and Cronbach’s α was 0.70. TRACK scores showed significant correlation with the medical and family opinions about symptom control (r: 0.74 and r: 0.61). TRACK scores were significantly lower in children who had used systemic steroids (median [IQR]: 45 [30–65] vs 75 [55–80]; p < 0.001) and had an emergency visit in the last month (45 [35–60] vs 70 [55–80]; p < 0.001). TRACK scores were also significantly different when children were separated by the medical opinion, GINA criteria and symptoms. Comparison of different respiratory symptom control cut-off points showed that the cut-off of 80 points had the highest area under ROC curve (0.800).ConclusionWe have demonstrated that the Portuguese version of the TRACK questionnaire has satisfactory reliability (internal consistency), adequate criterion validity (compared against GINA levels of control) and constructive validity (compared against respiratory symptoms and medical opinion), showing that it can be a useful tool to discriminate among children with different levels of respiratory symptom control.Trial registrationClinicalTrials.gov: NCT03290222.