<b>Background</b> The forced oscillation technique (FOT) is regarded as useful to assess airway patency and response to bronchodilators but its agreement with spirometry in outpatients is still debatable. <b>Aims and objectives</b> To assess the relationship between FOT and spirometry measurements in outpatients reporting recurrent respiratory symptoms. <b>Methods</b> Seventy-five outpatients, aged 5-18 yrs (40 males) did FOT measurements at 8 Hz of inspiratory (ins) and expiratory (ex) resistance (Rrs) and reactance (Xrs), and spirometry, both at baseline and after inhaled salbutamol 200 mcg. Baseline FOT values and bronchodilator changes were expressed as z-scores (z-s). Cut-off values for airway patency were FEV₁&lt;80% and FEF_25-75&lt;60%; bronchodilator response (D) was set as DFEV₁&gt;12% from baseline. Specificity was sought &gt;90% to reduce false positive results. <b>Results</b> Inspiratory FOT variables correlated better with spirometry than those expiratory (Rrs_ins with FEV₁: r=-0.51, with FEF_25-75: r=-0.62, p&lt;0.001). At specificity &gt;90%, z-s values of Rrs_ins &gt;2.46 predicted FEV₁&lt;80% with a sensitivity of 53.8% and FEF_25-75&lt;60% with a sensitivity of 66.7%. Post-salbutamol changes in impedance correlated better with DFEV₁ than DFEF_25-75 (DRrs_ins and DXrs_ins with DFEV₁: r=0.48 and r=0.50, p&lt;0.001). At specificity&gt;90%, a fall in DRrs_ins&nbsp;&gt;-2.43 z-score (&gt;-38.0%) predicted DFEV₁&gt;12% with a sensitivity of 36.8%, while increases in DXrs_ins &gt;1.65 z-score (&gt;64.0%) predicted DFEV₁&gt;12% with a sensitivity of 57.9%. <b>Conclusions</b> FOT and spirometry correlate fairly; wide FOT z-scores are needed to reduce false positive results on airway patency and response to bronchodilators.