Spirometry and peak expiratory flow measurement (PEF) are combined during functional respiratory assessments. The new digital peak flow meter (DPM) evaluates the forced expiratory volume in the first second (FEV 1 ) and PEF. To compare lung function measurements using spirometry and DPM. This cross-sectional analytical study assessed FEV 1 and PEF in children with and without asthma. Statistical analysis was performed to assess the agreement between the measures using the intraclass correlation coefficient (ICC), Bland-Altman, and survival agreement plot. 125 (3-12 y) and 196 (6-18 y) children without and with asthma, respectively, were studied. In children without asthma, the ICC for FEV 1 and PEF were 0.89 and 0.86, respectively, while the corresponding values were 0.87 and 0.79, respectively, in patients with asthma. The Bland-Altman method showed a difference of −0.4 to 0.5 for FEV 1 in patients without asthma, with a tendency to increase as the FEV 1 increased to a certain extent. In patients with asthma, the pattern was similar for FEV 1 , and the PEF had a greater dispersion than among those without asthma; however, a good agreement pattern was maintained. In the survival agreement plot, when accepting a tolerance of 0.150 mL for FEV 1 , there was an agreement of close to 55% in both groups. Likewise, when accepting a tolerance of 0.5 L/s for PEF, an agreement of close to 60% and 50% was observed in patients without and with asthma, respectively. DPM was effective as a measure of lung function in pediatric patients with and without asthma.