FEV 1/FVC normally decreases through childhood, increases briefly during early adolescence, and then declines throughout life. The physiology behind this temporary increase during early adolescence is not well understood. The objective of this study was to determine if this pattern also occurs in children with asthma. Design: Single-center, cross-sectional, retrospective analysis of pulmonary function tests (PFTs) obtained over a 5-year period in children 5 to 18 years of age with persistent asthma. Results: 1,793 patients satisfied all inclusion and exclusion criteria. Mean age (± SD) was 10.4 ± 3.8 years. 48% were female. Mean FEV 1 /FVC was 0.83 ± .09. FEV 1 /FVC in children with persistent asthma declined from age 5 to age 11 by 5.7 % compared to 7.3% in healthy girls, and 5.8% compared to 9.4% in healthy boys. FEV 1/FVC increased by 1.2% until age 16 in children with asthma, compared to 2.2% in healthy girls, and 2.5% compared to 2.3% in healthy boys. The ratio was lower in obese children with asthma at all ages but demonstrated the same curvilinear shape as in healthy children. In absolute terms, FEV 1 grew proportionately more than FVC during early adolescence, so the ratio of FEV 1/FVC increased during that period. The curvilinear shape of the curve remained in postbronchodilator testing, though significantly blunted. Conclusions: The “Shepherd’s Hook” pattern in the FEV 1/FVC curve is preserved in children with persistent asthma. This was also true in obese patients with asthma, although their FEV 1/FVC ratios were lower throughout all stages of childhood and adolescence.